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Friday, October 28, 2011

The 'Other' Invasion of Normandy and the Bayeux Tapestry

“Luke, you are going to find that many of the truths we cling to depend on our own point of view.”  Obi-Wan Kenobi in The Return of the Jedi.
Ben teaches Luke the rudiments of relativism!
 
This blog began with the rather extreme assertion that the French and English are really surprisingly similar people, despite rather different geography, languages and cultures and their own heated opinions.  Many divergences remain, of course, but it is difficult to escape the idea that in 1066, a great convergence began when Guillaume, Duc du Normandie beat Harold Godwinson at the Battle of Hastings.  In the sleepy Norman town of Bayeux resides one of the great historical records of that conquest, the Bayeux Tapestry, a visual document designed to provide the definitive account of that dramatic conflict, and carefully preserved down through the centuries.  Our tour of the World War II battlefields takes a time-out to traverse an additional 880 years of history when the Normans came as ‘liberators’ to free England from an evil usurper.  Depending on your point of view, apparently the “Crusade in Europe” -- Eisenhower’s term for the American participation there in World War II -- can look rather similar to the Norman Conquest.  Or maybe not so much…

A single panel of the Bayeux TapestryEdward the Confessor orders Harold to inform William of the latter's inheritance
 
It may be crewel to suggest, but the Bayeux Tapestry is, in fact, not a tapestry at all, but embroidery.  The original legend is that it was stitched by Guillaume’s wife (Queen Matilda) and her ladies-in-waiting, but modern historical research favors the needlework to Bishop Odo, Guillaume’s half-brother.  Its dyed wool embroidery was worked on a linen background  (but was not actually crewel either!) and was of a type renowned in England at the time of the Conquest, and was almost certainly executed by religious brothers in Kent, Odo’s bishopric.  The textile is a foot and a half wide and over 230 feet long, and was probably designed to decorate a newly built cathedral.  It is now displayed in Musée de la Tapisserie de Bayeux where long lines of people gather to view it.  While not woven like a tapestry, this piece functions as one.  The medieval French word for tapestry and embroidery were the same which explains why it is called a tapestry.  This language problem is only one of many ways in which the incomplete Frankification of England has resulted in far less similarity than might be expected – and more room for misunderstanding.

On display in Le Musée de la Tapisserie de Bayeux,  but minus the crowds
 
The central misunderstanding of concern in the Bayeux tapestry is not that it is not strictly a tapestry, but who should succeed the dying 11th Century English monarch, Edward the Confessor.  You may recall that Edward was responsible for beginning the construction of Westminster Abbey, his final resting place.  The Bayeux Tapestry tells the story of how Edward named Guillaume/William as his rightful heir, and how Edward required Harold to travel to Normandy to convey this message to William.  Harold was captured en route, and was finally freed through William’s intervention.  Upon delivering the message, Harold swore fealty to William and they campaigned together against William’s southern enemies, where Harold distinguished himself in William’s service.  Later Harold returned to England, only to recant his oath of loyalty to William, rebelliously leading a group of English lords and getting crowned King of England by a cleric of dubious authenticity.  

Signs and Portents:  The cosmology behind the Great Chain of Being required heavenly bodies to travel in perfect circles.  Comets obviously didn't do so, and were signs of evil and disorder in the heavens and harbingers of disaster here on Earth.
As the tapestry depicts, evil signs and portent’s provided ample evidence of God’s displeasure, where upon it became William’s holy obligation to punish this oath-breaker.  William duly built an immense fleet and army, traveled to England, built a wooden castle there, and finally cornered Harold, and an immense and bloody battle ensued.  After a ferocious struggle against Harold’s mighty shield wall, and with great loss on all sides, Harold was killed. The tapestry is thought to have then displayed a small final segment  showing William’s coronation but, if so, that segment no longer exists.  In the version we saw, English warriors are seen retreating from the battlefield with William victorious.  The thrust of the tapestry’s narrative is that William had every right and obligation to make war on Harold, that his punishment was required by the violation of Harold’s oath of fealty, and that William was the rightful owner of lands given him by Edward the Confessor’s wishes.  From this point of view, the Norman Conquest was no conquest at all merely a transfer of leadership to its rightful heir.

The Normans disembark at Pevensey
The Bayeux Tapestry is beautifully rendered and compellingly told.  It is one of the first graphic novels, complete with Latin narration, a precursor to the Renaissance banderoles sans the cherubim and artful scrolling.  There are no modern dialogue balloons.   The embroidered narration identifies the key characters, locations and plot developments.  The Tapestry was clearly designed to inform the literate and illiterate alike, at a time when there were a great many more of the latter!  As one walks the 240 feet around the displayed work, it appears very like a modern story board.  Depictions of the weapons, armor, ships, fortifications and personalities provide detail about military, political and social practices of the time, such that the Bayeux Tapestry is both a political polemic and a valuable window into medieval life from which little direct documentary evidence remains.  The state of its preservation seemed remarkable to this writer, who is by no means a trained art historian and certainly not a textile specialist.

Harold's housecarls (knights on foot) use their shield wall to repel William's mounted knights during the Battle of Hastings.
 
The Bayeux Tapestry story of William and Harold leaves out much that modern historians have since learned about the Norman Conquest, including some critical pieces of the story.  To non-partisans, Edward the Confessor’s death left his wishes for the succession to the English crown ambiguous.  Historians are unsure who, if anyone, he named.  Harold was supported for the kingship by a broad coalition of English nobles who didn’t fancy serving a French monarch.  Harold Godwinson’s estranged brother, Tostig, Norwegian King Harald Hardrada, Sven Forkbeard, King of Denmark, as well as William of Normandy all had claims to the throne.   

The modern version of the Bayeaux story goes something like this.  King Harald Hardrada attacked Britain first, landing near York with about 9,000 men, but Harold Godwinson marched north from London in September of 1066 with an army of 15,000, many of whom were conscripted local peasants, or levies.  Harold utterly defeated the Norwegians in a long sanguine affair, catching the Viking army of 9,000 by surprise and without their armor in the Battle of Stamford Bridge across the Derwent River near York on September, 25, 1066.  This crucial defeat ended the Norwegian claim; Harold killed  both Harald and Tostig, losing about a third of his own men in the process.  Three days later, William’s force of about 7,500 landed on the south coast of England at Pevensey.  Tired and depleted, Harold rushed south, loosing many of his local levies to the harvest season in a march of 250 miles over indifferent roads.  After a brief stop in London for fresh levies, Harold brought his 7,500 tired men to Hastings.  On October 14, 1066, he took good defensive positions on a hill.  William attacked and the battle was hard and evenly fought and until counter-attacks against the Norman cavalry depleted Harold’s troops and disorganized the effective shield wall.  Late in the day, the English shield wall broke and Harold was killed.  This did not quite break the English resistance, but William was crowned King of England in Westminster Abbey on Christmas Day, 1066.  Perhaps persuasive pieces like the Bayeux Tapestry – telling a story that justified William’s reign - were deemed necessary by Bishop Odo as scattered resistance to Norman rule would continue for the next twenty years.  As mentioned in my former post London:  The Bridge and the Tower, the central keep of the Tower of London, White Tower, was begun in 1078 by William to consolidate his control over a restive populace.  

Key locations in the campaign of 1066


The center of this panel depicts the climactic death of Harold Godwinson.


By way of convergence, The Norman victory at Hastings is seen as fundamentally transforming the English language and culture with French ideas and idioms.  The Anglo-Saxon aristocracy was largely displaced and scattered, and the remaining aristocrats largely merged with the French so as to become indistinguishable after several centuries.  Nevertheless, a long series of crossed political claims bound the English and French in rivalries that continue in some ways even now reinforced by a long series of wars between them, particularly in the Hundred Years War (the topic of my next post) and the period between the 16th and early 19th centuries.  So contentiousness about the events of 1066 persists to this day.

Passion to reenact Hastings persists too.  These fellows from Sussex are wearing 55lbs of gear.  It is a good thing they didn't march from Stamford Bridge in it!


Despite propaganda, rivalry, imperialist ambitions, and persistent nationalist pride, the French and English remain bound by deeper shared sensibilities.  Less than a mile a way lays the Bayeux Commonwealth Cemetery, final resting place of 4,141 British and 466 Germans who died in the Allied invasion and liberation of France in World War II.  On the memorial, inscribed in Latin is the British acknowledgement:

“We were defeated by William, but liberated the land of the Conquerors.”

The Memorial at Commonwealth Bayeux Cemetery

Thanks to Cruise Director Extraordinaire AJ and Amy Williams, both of Uniworld for helping me identify the final quote.  No, they did not pay a promotional fee for this endorsement, but they certainly earned special thanks!

A J, Cruise Director Extraordinaire plies his simple trade while a shadowy figure looks on

Tuesday, March 22, 2011

Overlord IV: The D-Day Landings




“No plan survives first contact with the enemy.”  Helmut von Moltke the elder.

Helmut von Moltke the eldar was a famous Prussian military planner.  His principal claim to fame was designing the railroad mobilization plans for the Franco-Prussian War 1870-71.  As such he was the architect of the French defeat.  So he probably knew a thing or two about planning. 
The weather reports received by SHAEF on the evening of June 4th, 1944 were not good.  Rain and high winds were blowing in off the Atlantic, and seas were marginally too high to permit a landing on June 5th.  Predictions for June 6th were mixed.  Eisenhower decided to call off a June 5th invasion.  Paratroopers, all dressed up with no place to go, unloaded from planes at their home landing strips.  Nervous seasick troops did not even enjoy that small luxury.  Most remained at sea in their British anchorages as Eisenhower set the small hours of June 6th as time for the final decision about whether it might just clear enough to go at dawn.   The early June invasion window afforded by favorable tides and a full moon had come, but now it looked as if bad weather was going to close it.

As geography would have it, the prevailing winds blew for west to east.  The Allies had the foresight to station weather ships in the mid-Atlantic and could wire much more detailed information to SHAEF meteorologists about upcoming conditions than their German counterparts enjoyed.  As the Allied commanders struggled with indecision about whether to invade, the Germans, with only the information from their troop positions on the French coast to go on, concluded that a several-day storm was upon them.  They decided no invasion could come in the next three days.   On June 5th, several generals, including Erwin Rommel, went back to Germany for personal time or conferences.   Rommel looked forward to celebrating his wife’s birthday.  When Eisenhower received the reports from his meteorologists in the early morning of June 6th, a very modest improvement was predicted. Conditions would be far from optimal, but might be just good enough to go.  The Allied commanders now weighed the risks.  They were divided, but leaned towards invading immediately for fear of loosing surprise about the landing sites.  In the end, Eisenhower had to make the final decision himself.  He struggled with it, but he chose to take the risk of invading right away.  And his choice paid off.  Because the Allies had better weather data, their invasion would catch the German commanders far away from their posts.

Ike and his commanders in an early planning meeting for the invasion.  These men advised Eisenhower when it was time to make the decision to invade in the face of bad weather.

Codes were sent activating the French Resistance, requesting them to attack prearranged targets not easily knocked out from the air.  The Americans and British had been supporting the French Resistance with supplies and OSS advisers for three years.  Now was the time to make their contribution count most.  On the ground, secretly ensconced behind enemy lines, the French Resistance could sabotage facilities that were too hard to hit, or too easily repaired for air attack to suppress at this critical time. 

The first Allied soldiers to touch French soil were the paratroopers.  One thousand air transports carrying the three divisions of airborne units initiated drops east of Caen to secure the eastern flank of the planned invasions by sea and on the western flank in the Cotentin Peninsula behind Utah Beach.  The airborne units were expected to obstruct access to the beaches to any reinforcements the Germans might send to the invasion sites.  They were to seize strategic bridges and towns on the main roads to the beaches.  Some had orders to destroy strategic heavy gun emplacements that could rake the beaches and disrupt the landings.   It was also hoped that the sudden presence of so many Allied troops behind German lines would sow confusion among the defenders, and obscure for as long as possible the exact Allied points of attack.  

Parachutists dropping in daylight.  This photo is not from the Normandy assault itself, which took place in darkness, but they jumped from identical Dakota transports.

The hope placed on paratroopers, however, proved to be unrealistic for many reasons.  First, being lightly armed, the troops would have to hang on where they landed until support (armor and artillery) could struggle up to them from the beaches.  Second,  high winds, inexperienced pilots and enemy fire meant that many were killed on entry and many of those who landed alive were badly scattered.  This was less true for the British 6th Airborne Division on the east.  These troops were mostly dropped on target and had secured their objectives within an hour of landing.  The US 101st Airborne Division, on the other hand, was scattered in a 10 by 25 mile ellipse all over the Cotentin Peninsula.  Clouds obscured the moon and pilots couldn’t identify the landing areas.  Some troops were dropped into the sea where they promptly sank and drowned.  Some were dropped too low and hit the ground before their parachutes were opened.  The US 82nd Airborne Division also landed dangerously, being dispersed around the town of St. Mere Èglise, which was already garrisoned by the Germans.  Some troops there were shot as they descended or jumped from burning transports hit by anti-aircraft fire.  Their night became a screaming confusion of German tracers converging on descending troops and fire exchanged with Germans on the ground before they had even touched down.  The messy situation at St Mere Èglise would take hours to resolve before the Americans could secure the village. They were so scattered and intermingled with troops from the other airborne division, they would have to overcome great disorganization to achieve their initial objectives.  It was made even more difficult, because the Germans had flooded low lying areas behind Utah Beach, and a number of paratroopers drowned in the shallow waters, and these proved a significant obstacle to concentrating the scattered paratroopers.   Despite all these formidable obstacles, the Americans also achieved their objectives.

A contemporary aerial photo of St. Mere Eglise, the center of the 82nd Airborne's drop zone.  The large building at the crossroads is the church where a trooper hung suspended through much of the battle.  He was played by Red Buttons in The Longest Day.

At the first signs of gray dawn, Allied tactical air forces 14,000 plane-strong started to bombard the battle area.  With the paratroopers already on the ground and the troops about to hit the beach, it was time for air attack to soften up the landing zones and try to disrupt enemy troop concentrations behind the beaches so they could not reinforce the critical points of attack. Thousands of flights would be conducted on June 6.  The initial bombardments looked spectacular from offshore, but were largely ineffective at damaging the German defenses.  Most bombs fell too far inland to help the beach landings much.  The Germans were too well dug in, and Allied intelligence and bombers too imprecise to do much more than confuse the Germans.  However before the shore bombardment started and the first troops reached the beaches, the sum of Allied deceptions -- the tactical air strikes, the parachute drops, and the disruption of German communications and the specific attempts at deception -- all meant no concerted German effort would get made against the Allied beaches during the crucial initial 24 hours.  The Germans would fail to get any units into the battle area on June 6 that had not already been stationed there prior to the Allied landings.

Higgin's Boats lining up for the D-Day assault next to an attack transport.

A fleet of 7,000 ships proceeded to the five main landing zones.  There were battleships and cruisers to perform shore bombardment, minesweepers to clear naval mines that might block the beaches.  There were destroyers and patrol craft to protect the troop transports and amphibious assault ships from German patrol boats and submarines that might lurk in the area.  And there were thousands of landing craft to carry the invading troops and their heavy equipment from the troop transports to the beaches themselves.  Finally, there were transports full of equipment and supplies to support the landing armies once they were ashore. The fleet that assaulted Normandy on June 6, 1944 remains the largest fleet ever assembled.
Naval bombardment as seen from the bridge of a heavy cruiserShooting was easy.  Hitting fortified positions effectively was another matter.

The results of pre-invasion naval gunfire and aerial bombardment.  Pointe du Hoc was the site of fortified gun positions west of Omaha Beach.  The U S 2nd Ranger Battalion gallantly scaled the 150 foot cliff in the face of enemy fire on the morning of D-Day to silence heavy guns that could rake the Omaha and Utah landing sites.  None of the gun emplacements had been damaged, but when the rangers arrived, neither were there any guns!  Rommel had ordered them removed on June 4, but they were found nearby and destroyed.

The Allied shore bombardments were not initially very effective, but as the day wore on, noteworthy gun duels would happen between some German forts and Allied ships.  The Allies naval bombardment would eventually win all of these.  The Germans had more success attacking the landing craft.  In some places, they were able to destroy all the tanks before they could reach the beaches. They hit many landing craft on route to the beaches.  In other places their heavy fire forced landing craft to stop short and disgorge their troops in water too deep for them, drowning entire platoons.  But the huge fleet was completely effective in three key areas.  No German submarines or patrol craft interfered with the June 6 landings, no ships were lost to German air attack, and by the time the day was over each landing had secured the immediate beaches and had advanced somewhat inland.  Only a tiny percentage of the Allied warships was sunk.  While all of the beach landings had failed to penetrate as deeply into the Normandy countryside as had been hoped for by the original plan, the Germans utterly failed to prevent any of the five landings.

The beach landings would occur at 5 sites, ranging along 50 miles of the Normandy coast from directly in front of Caen to the base of the Cotentin Peninsula.  Each was code named; from east to west they were Sword, Juno, Gold, Omaha, and Utah.  Because of the tides, the troops went in from west to east.  The Commonwealth forces took the eastern three beaches, with the British taking the lead at Sword and Gold, and the Canadians at Juno.  Free French units landed with the British at Sword.  The Americans landed at Utah and Omaha.

Utah Beach invasions sites and advances inland, June 6 1944

At Utah, the US 4th Infantry Division caught two lucky breaks.  Because of delays and stronger currents, they missed their target beaches and wound up two miles further to the west than planned.  The beaches on which they actually landed were more lightly defended than the original targets.  Their second break was that the troops they faced were primarily Ost battalions; Russian and Polish recruits to the German Army who sometimes fought poorly compared to German veterans.  While landing on the wrong beaches caused plenty of confusion and delay, troops were moving inland in good order by noon, and lead elements of the 4th Division linked up with scattered elements of the American parachute divisions later that day.  The Utah landing force would lose only 12 men killed on the beach, and only 200 casualties during the first day’s fighting. 

Omaha Beach was next.  This is the site of our tour this morning, and the experiences of these troops were completely the opposite.  This is the main site we visited, and it will be described last.

Gold,  Juno and Sword Beaches and the Commonwealth Forces' advance inland, June 6, 1941.  The dashed red line indicates the Allied planners' optimistic initial objectives.  Our tour bus skirted Caen, which has since acquired a beltway, and we stopped only at Arromanches.
Gold Beach today at Arromanches, with some parts of the Mulberry still in place.  We viewed the beach from the village at the upper left.

Next came Gold Beach, between the tiny fortified villages of Arromanches and La Riviere.  The British 50th Infantry Division at Gold and the Canadian 3rd division at Sword landed immediately adjacent to each other, and were spared the problem of linking up with each other once ashore.  The British did have the problem of trying to find the US forces landing 3 miles away on their right flank. The flail tanks and armored bulldozers of Hobart’s Funnies proved instrumental in clearing safe lanes through the obstacles and minefields on the beaches, and the German strong points were overcome in the first hours.  The water was too rough here for the Dual Drive Tanks designed to swim ashore under their own power, but the beaches were cleared so quickly that they were landed conventionally and were supporting the British advance six miles beyond the coast by mid-day.  By the day’s end, units of the 50th Division would advance to the outskirts of Bayeux, the first town to be liberated.  They were searching for the Americans on the left, but no link up would be managed with the Americans landing at Omaha until June 9.  The Gold Beach force suffered 400 casualties despite the need to take fortified villages; a serious price to be sure, but far beneath the planners’ most conservative estimates.

Juno Beach from the air, taken during the landings.

The Canadians landed at Juno Beach at the same time the British were arriving at Gold Beach.  Juno was more heavily defended by a single German static division.  Although these were fortress troops with little ability to maneuver, they fought well.  Nonetheless, the Canadian 3rd Division overcame the beach defenses in the first hour and was able to advance inland almost 10 miles before pulling back some units because they could not be properly supported in the event of a German counter-attack.  Casualties were heavy: 2000, including 600 dead.  They were the only troops to have attained the first day objectives set by SHAEF, although these positions could not be secured because adequate forces could not be moved up before nightfall.

British Tommies return to the continent at Sword Beach.

On the extreme east, the British 3rd Infantry Division, augmented by tanks and Free French units, assaulted an area of beach between the villages of Ouistreham and St. Aubin-sur-Mer.  Their immediate objectives were to secure bridges over the Orne River on their East, and to attack south and seize the city of Caen, and to link up with the Canadians on their right.  In practice, these objectives proved wildly optimistic.  The city was garrisoned by the 21st Panzer Division, which had upwards of 160 tanks and assault guns -- essentially tanks with no turrets.  Again, the initial confusion of the Germans and the effective use of specialized tanks designed for combat engineering carried the day.  Here was the only place where the Allies had to face German armor on the first day, and although the British managed to destroy about 50 German tanks, they only reached the outskirts of the city by nightfall.  Elements of the 21st Panzer Division advanced from Caen to the coast between the Sword and Gold beachheads.  They believed that the German hold on this coast was secure, and rather than risk what might be further paratroop assaults to their rear, they pulled back to Caen by nightfall.  Had this division taken a more careful look – or been less afraid of a threat that turned out to be mistaken – they might have used their armored forces to crush the vulnerable beachheads.  The performance of this one division suggests that the Germans’ pre-invasion debate (and the Allies fears) about stationing panzers on the beaches was misplaced.  Perhaps even three or four more divisions would have failed to crush the Overlord assault.  But 21st Panzer provided a stiff defense of Caen in the coming weeks.  By the evening of June 6, the Sword beach force had suffered over 2,500 casualties, but it would be a month before they captured Caen, their first day objective!

The West Point Map of US operations at Omaha, June 6, 1944.  This was chosen for the inset at the bottom that shows the relative heights of the seawall and bluffs at Omaha.

As severe as the British test was on Sword, it would pale in comparison with the American ordeal in store at Omaha beach.  There, American’s found themselves short of tanks that could have provided assistance to their landing troops.  They had felt confident that they could decline the British offer of specialized tanks, but probably regretted it when many of the conventional tanks they had sent to the beaches were destroyed before they reached the shore.  Omaha Beach, we found, was about 3 miles of relatively level sand framed by grassy hills that were perhaps 150 feet high.  The assaulting troops had to get off the exposed beach as quickly as possible and climb the hills that lead to the plateau that comprised the Norman countryside, but those hills were steep, well-fortified and manned by veteran German infantry.  

A contemporary aerial view of the Omaha Beach landing site.  In the upper left are the landing beaches.  On the extreme right are the Pointe du Hoc cliffs the rangers had to scale.
The initial American assault conducted by the US 1st and 29th Infantry divisions went in at 6:30 AM and was decimated.    The rough seas scrambled the landings, and units arrived at the wrong beaches. The pre-invasion bombardment was ineffective.  Many landing craft were hit by artillery before they reached the shore.  Where the craft landed, the Germans held their fire until the ramps descended, and then opened up.  In some units, no one came to shore without having been injured before they left the craft.  When survivors struggled to the shore, there were no craters to hide in, and the initial waves of men found the beach heavily mined.  Troops tried to hide in the water behind the German obstacles and eventually struggled to the sea wall.  With no way to retreat, they simply huddled as best they could as successive waves of troops came in.  The dead soldiers’ bodies added to the wreckage and confusion.  Allied gunfire, meant to cover the landing men, was not effective at neutralizing the German fire, because the ships were ordered to stay too far out to sea to protect against the danger of running aground in shallow waters.  The beaches began to clog up with the refuse of shattered units and dead men.  By mid-morning the US Corps commander, Omar Bradley considered abandoning the Omaha Beach assault all together.

A famous contemporary photo of troops wading ashore during the first wave.

A German machine gun position at Omaha Beach as depicted by Steven Spielberg in the opening sequence of Saving Private Ryan.

As the morning wore on, the Americans began to improvise.  The lighter naval units defied orders and approached to within 1000 yards of the beach, improving their ability to pinpoint fire that could knock out German positions.  Most of the units that comprised the first and second waves of the assault lost over 40% of their manpower from casualties and scattering.  Although that kind of loss severely degrades a unit’s effectiveness, individual soldiers began to take the initiative to get off the beach. They faced daunting obstacles:  barbed wire, mines, and German pillboxes housing heavy automatic weapons defending all the draws that led up the hills off the beach.  But they salvaged the engineering equipment from the corpses and jetsam on the beach and, with naval gunfire support, began to take out the pillboxes and infiltrate behind them.  By noon, exhausted ad hoc units had cleared two of the draws off the beach, which was still jammed with the jumble of newly arriving units amidst the un-cleared wreckage of the morning’s battle.  Combat engineers would take heavy casualties under fire building the roads off of the beachhead through which the afternoon’s reinforcements would advance.  At Omaha Beach, just as it is depicted in the movie Saving Private Ryan, the survivors of shattered units came together to improvise their way off the beach when all the plans had failed, and only bravery, individual creativity and perseverance could salvage the job.   Moving from open ground up through hills hiding armed enemy soldiers is one of the most daunting challenges foot soldiers face.  In the Civil War, at Marye’s Heights in Fredricksburg, the Union soldiers, possessed of courage, creativity and perseverance never got up the hill.  But against automatic weapons and fortified positions, the American combat infantry got off the utterly exposed beach and into the Norman countryside against all the odds.

The Normandy American Cemetery and Memorial as seen from the air.  The pavilion at the top has huge maps of Allied operations on the West Front of World War II.  To the left is Omaha Beach itself.  Beyond the woods at the top of this picture is a museum which reverence and bus schedules afforded too little time for us to see.

The Normandy American Cemetery and Memorial at Colleville-sur-Mer sits at the top of the same 150 foot bluff those American’s fought their way up on June 6, 1944.  It is not the resting place for most of the 2,000 dead Americans that came ashore in the rough gray hours of that morning.  That evening, burial details started to gather up the bodies and bury them under the bluffs, between the roads the engineers had cleared up from the beach.  These would be heavily trafficked in coming days as additional units arrived.    It did not take long for the commanders to realize how demoralizing it could be to have these men march past those grim reminders of the risks of the campaign ahead.  So the bodies were moved and reburied elsewhere, well before the present cemetery was established.  So those resting today at the main cemetery at Colleville-sur-Mer were mostly killed after that bloody June 6th invasion. 

Now the cemeteries at Normandy are green and peaceful places, filled as they are with all those who died in the horrors of organized violence through out the ensuing liberation of France and the Low Countries, and the invasion and final defeat of Germany.  Nearly 10,000 American war dead are buried here in view of the location of that original bloody assault.  It is a beautiful place, even on an entirely gray day where the sea of the English Channel and the sky readily merge in an indistinct horizon.  The day of our visit was not the clear day upon which you might imagine that you can make out the distant shore of southern England.  Many of those two thousand dead have long since been repatriated to the US at the discretion of their families.  Those that remain are mixed among the dead of the many other campaigns that comprised the Allied Western Front from June of 1944 though May of 1945.  The Normandy Campaign alone would cost the Allies 120,000 casualties, and the Germans perhaps as many as 450,000.

The Cemetery is territory of the United States, having been donated for this purpose by France so Americans who died for France’s liberation could be buried on 'American' soil.  It is operated by an American concession and a charity provides all visitors with a flower that can be placed on one soldier’s grave.  My companions from the tour bus fan out to select a grave for their flower, and all conversation becomes hushed.  Perhaps it is fear of death, or reverence for the dead, awe at their sacrifices, or shame and relief that we have not had to give that last measure of devotion our country required of them that lowers our voices.  If you have seen the opening sequence of Saving Private Ryan, as the elderly Ryan visits the grave of Captain Miller, you will recognize the orderly rows of crosses and the very occasional Star of David.  They say there are no atheists in foxholes, and apparently not in cemeteries either, for each grave is marked with one symbol or the other, and all the unknown soldiers are marked with a cross.  We selected an unknown grave to decorate with our flower, imagining that no family would know to visit a lost soul and that his sacrifice must be all the greater to have surrendered not only life, but identity, in the battle.

Matt Damon salutes Captain Miller at the conclusion of Saving Private Ryan.
The 43rd President of The United States visits Normandy American Cemetery on the occasion of the
65th anniversary of D-Day.


That desperate struggle on June 6 was only the beginning of the Normandy Campaign.  But it proved to be far tougher going than the Allied planners had expected.  Ancient hedge rows of the bocage surrounded the small French farms of this section of Normandy, and these provided natural fortifications that were impenetrable for Allied tanks.  Centuries of growth created sunken roads, making for countless opportunities for ambush.  The build up of soil made natural embankments too thick for ordinary tanks to bulldoze their way through.  The foliage provided natural cover and excellent concealment for snipers.  The Normandy battle quickly devolved into a battle of attrition as the Germans gradually fed their reserve formations into the battle.  These naturally arrived first at the eastern edge of the Allied lines, nearest Juno, Gold, and Sword beaches, so going was slowest for the Commonwealth forces there.  It would take three major operations and four weeks before the British and Canadians had liberated Caen.  As the Germans were pressured in the fight for Caen, the western side of their lines became weaker.   It would take the Americans a week of fighting to cut off the Cotentin peninsula and isolate Cherbourg.  When the port city finally fell on June 27th, the Germans had wrecked it so badly that it took the American engineers two weeks to clear the harbor.  By the time it was fully functional, the Allied armies would already be driving for the German border.  

French hedgerows; the bocage, from the air.
A Sherman tank in the bocage.  Not so picturesque if you have to fight for them!   Tankers prefer open ground and clear fields of fire.  Defenders prefer concealment and the opportunity to get close.  The Allies thought they had hedgerows all figured out, because they divide plots of land in British farms too, but the French hedgerows are far more ancient, dense and the roads more sunken.

By the afternoon of June 6, shipping began unloading at Omaha Beach and would continue to do so until June 19th.  Throughout the Normandy campaign and beyond, the Allies struggled to keep the American, British and Free French armies supplied and to build up forces. These are large landing craft for unloading vehicles directly on the beach.  The Omaha Beach Mulberry was not yet assembled when this photo was taken.

The Allied build up was greatly facilitated by the use of Mulberries, or temporary man-made harbors, constructed at Arromanches and at Omaha Beach.  On June 19st, (the next invasion opportunity if Eisenhower had not given the go ahead on June 6th) a 100-year storm blew in from the Atlantic and wrecked the American Mulberry. The remains of the surviving temporary port can still be seen when we visit the museums and commemorative plaques at Arromanches.  On the beach, you can see Sherman tanks and British 25-pounder field guns, souvenir shops and concessions.  If you look out in the water, you might see the hulks of the Liberty ships that were filled with concrete and sunk to make the Mulberry breakwaters.  And you might imagine how the Mulberries themselves became temporary docks on which to unload the endless stream of ships supplying the Allied build up.  Everything the Allies needed had to be shipped through these makeshift facilities.  When the June 19st storm came, and interrupted supply for three days, both the British and Americans had unloaded 9,000 tons of troops and supplies daily through these makeshift port facilities.

Patton's forces breakthrough at St. Lo and nearly pocket the Germans at Falaise, and end the Normandy Campaign.  By the end of summer, almost all of France had been liberated. 
Almost all of the Allied combat formations had truck transport, and were far more mobile than German static divisions, which scarcely moved at all, and German ‘leg’ infantry which had to march on foot.  If the Allies achieved a breakout from Normandy and caught German formations beyond the natural fortifications of the bocage, the German Army was in danger of disintegrating, unable to disengage from faster enemies.  After 8 weeks of slogging attrition warfare, the Americans achieved exactly that breakout, on the weaker western side of the German front at the village of St Lo.  Following a German armored counterattack which Allied intelligence had pinpointed and was soundly defeated, the American mobile formations assigned the General George Patton made skillful use of these natural mobility advantages to nearly surround and isolate two German armies.  Despite a skillful withdrawal, by August 25th, the Germans lost 50,000 prisoners and several thousand vehicles, and their forces completely disintegrated south of the Seine.  By this time, the German commander, Erwin Rommel, had been seriously wounded when his staff car was strafed by Allied aircraft, and he was out of the war.  On October 14, 1944, Rommel was coerced into taking cyanide by agents of the Hitler government in the mistaken belief that he was involved in the July 20th bomb plot against Hitler’s life, itself a product of the accumulation of serious military reverses like the defeat in Normandy. 

During the Normandy Campaign, Stalin launched Operation Bagration aimed at destroying German Army Group Center and recovering Belorussia and parts of Poland.  In material terms, Germany lost many more men and much more territory here than in France.  German generals, rightly fearful that Hitler would never negotiate peace, failed to assassinate the Fuhrer at his command bunker in East Prussia, July 20, 1944.  World War II in Europe would drag on until May 8 1945, and only ended with most of Germany overrun and Hitler dead by his own hand as the Soviets occupied Berlin in house-to-house fighting.
The Normandy Campaign resulted in an Allied strategic victory.  The Allies would face only isolated resistance until they reached the border of France and Germany and the Low Countries.  On June 22, the Soviets launched Operation Bagration, their massive summer offensive.  By August 14th they pocketed and destroyed an entire army group, resulting in the destruction of about 25% of the German Eastern Front forces and the loss of about 400,000 men.  On August 19th, the Paris Resistance rose and began to seize many parts of the city.  On August 24th Free French Forces entered an intact Paris despite Hitler’s orders that it be burned to the ground.  That Paris was not burned is a fascinating story in and of itself, and probably worth a post of its own later in our trip!  

However the most compelling story of the invasion isn’t the saving of Paris from being burned to the ground, or the brilliant technical innovations of Mulberries or Hobart’s Funnies.  It isn’t even Eisenhower’s decision to go for it on June 6th or the German’s decisive disorganization at the moment of the attack that lost them the chance to crush the invasion.  It was something simple – and for the Germans, there were several hours at Omaha Beach where the German commander had the troops at his disposal and could have caused thousands of shattered, exhausted and demoralized Americans to surrender with a modest attack by troops on hand, had he not thought the invasion already a failure!  He did not require tanks, merely the clarity and resolve to act with the forces at hand.  Instead they went to a sector that wasn’t even seriously threatened and accomplished nothing.  There would have been no Saving Private Ryan to film if 200 German infantry had made a concerted attempt to clear Omaha beach at 10AM June 6.

The history of D-Day is full of a thousand amazing accounts of dramatic, desperate and improbable events:  a man who helplessly watches street fighting below suspended from a church steeple tangled in the rigging of his parachute.  A paratrooper drowns landing directly into a well.  An American paratroop commander overloads his glider with protective plating and falls out of the sky like a rock.  German commanders are too afraid to release the Panzer reserves to assault the beaches without Hitler’s orders, but also too afraid to wake Hitler to get them.  A soldier draws his weapon on a frightened sailor commanding his Higgins boat so that his comrades will not be dropped in water too deep for them despite withering German fire.  

All of these stories are amazing.  There is nowhere near time to visit them all.  Instead, I stand for 15 minutes at the top of one of the fortified gullies disorganized American GI’s had to claw their way up in the face of fierce machine gun fire from German pillboxes on the late morning of June 6, 1944.  I am looking down at the peaceful beach now cleared of obstacles, and marvel the accomplishment of those shattered frightened Americans.  For many their first taste of battle looked like a bloody confused defeat.  They have lost their friends and their commanding officers, often their entire units.  Their situation looks far worse than anything they had imagined in training, or in their previous combat experience.  They have nowhere to run and are being killed where they hide.  Yet still they reassemble their wits, shake off their shock, fear and fatigue, and find a way to get up that impossible hill.

Omaha Beach today, viewed from the Normandy American Cemetery and Memorial, Colleville-sur-Mer.

Monday, January 3, 2011

Overlord Part III: The preparations.

"In preparing for battle, I have found that plans are useless, but planning is indispensable."  Dwight David Eisenhower

Command:

When, in 1942 America’s untested troops stormed ashore in Algeria and Morocco, FDR had appointed Dwight David Eisenhower to lead them.   After some heavy negotiations, Roosevelt secured his leadership for Operation Torch, the Allied invasion of North Africa.  The US would lead the invasion, despite no real battle experience against the Germans yet as of November of 1942, because the initial target would be French North Africa.  The French colonies in North Africa, after the Fall of France were defended not by German units, but by the Vichy French.  The Allies were hoping that, despite the legal fiction of neutrality -- French troops were actually functioning at the pleasure of the German victors -- the Vichy troops would not put up much of a fight.  There had already been serious friction between the British and Vichy when the British, concerned that the Germans might get control of some ships of the French fleet, attacked the French Navy in Vichy waters, so the British were probably not the best choice.  The French capitulated quickly after tense negotiations, and the success of the operation led to Eisenhower’s rise to commander of the Supreme Headquarters, Allied Expeditionary Forces (SHAEF) in December 1943.  His next major assignment was the planning of Operation Overlord.


Eisenhower was chosen because he was a diplomat as much as a warrior.  He had the responsibility of balancing the tough egos of the top British and American and Free French commanders who were competing with each other to show the largest contributions to the Allied war effort.  He also needed to manage the inter-service rivalries of all of those forces: strategic air forces, tactical air forces, naval and ground forces of each of those countries would need to be coordinated in such a massive and complex invasion.  There was ethnocentrism and competing agendas as well.   American foreign policy was explicitly anti-colonial, a severe sore point with their allies.   The Free French and the British were defending empires upon which the sun was just beginning to set.  Furthermore, the French were very eager to show they could liberate their own country, and fought the lead taken by the Americans or British despite the fact that America provided almost all of their transportation, equipment and supplies and many of their forces were staying in England.  So the plans that were worked out required a delicate balancing act from their commander.
Eisenhower planning for Overlord, flanked on his right (our left) by General Bernard Montgomery, commander of the British ground forces, and left by British Air Marshal Arthur Tedder, who helped Eisenhower battle British and American strategic air force commanders who did not want to subordinate their air offensives to the invasion plans!  This was Eisenhower's hardest fight of them all!
 
The invasion itself looked like a long odds gamble to the Eisenhower because of several factors.  The first limitation was that the invasion could succeed if it took place where the Allies could control the air.  Air attack on the landings needed to be prevented, which meant that the Atlantic coast of France was pretty much the only choice.  Southern Brittany was lightly defended but far from British ports and airfields, and far from the eventual objectives -- Berlin and the Ruhr industrial center.  Belgium and Holland were close to these, but too vulnerable to German air and naval concentrations to risk an assault.  French beaches had a large tidal surge, so only certain beaches were suitable, and timing had to be chosen with great care so that landing craft could sail over German obstacles and not disgorge the troops in water too deep for them, or too far out from the beaches.  Men in the water would be slowed down and too vulnerable to enemy fire.  If they landed in water over their heads, they would sink and drown with their heavy packs. Weather would limit operations.  It would be impossible to go if the seas were too rough or the skies too windy or foggy for the effective use of allied air or sea power.  A full moon was needed for airdropping the parachute divisions.  Germany had fortified the beaches with concrete pillboxes and artillery emplacements, mines, barbed wire and a host of obstacles.  And the Allies would only be able land a small percentage of their forces assembled in Britain in the first wave.  The Germans would have 58 divisions on or near the coast; the Allies would be able to land only eight.  The odds against success were pretty long -- unless the Germans could be prevented from quickly concentrating 58 against 8!  

Eisenhower's plan:  German Dispositions and Allied plans for the Battle of Normandy.  The crucial German panzer divisions are in dark red.  German units with an empty rectangles are fortress troops, those with an 'X' are regular infantry.  Pas de Calais is not marked, but is the area immediately east of Dover full of fortress troops, and targeted for an Allied diversion.  Those green areas in Germany were objectives of the British and American strategic bombing offensive that Ike needed to divert to destroy the French transportation system in preparation for the invasion.

Logistics:

Once the troops were ashore, they would require supplies.  Soldiers could only carry the food and ammunition they needed to fight a full effectiveness for two or three days, and much less than that if operations were going to be as intense and prolonged as could be expected.  The invading troops would be pitted against some of Germany’s best military units.  The Germans would have the use of the full French road and rail nets to supply their troops, and they had had years to create supply depots and fortifications to help support their troops.  The invading forces would have to carry everything on their backs initially.  For this reason, the Allies put a very high priority on quickly seizing a good deep water port and there were only a few really good ones along the entire French coast.  While the Allied troops weighed these factors in arriving at a plan, the Germans were also looking at them, trying to predict where their enemy would strike, and they were fully aware of the Allied supply challenges.  The best ports would be heavily defended.

Technological Innovations:

Nowhere is the story of Allied inventiveness more deeply validated than in the devising the technological solutions that made amphibious assault possible.  In all of World War II, as complicated and risky as these operations were, I know of only two failures.  The critical one was a raid on Dieppe on the coast of France in 1942.  This raid cost 3,000 Canadians their lives when they landed on well-defended beaches without the engineering capabilities to quickly overcome the German fortifications.  Despite the severe sacrifice, Dieppe taught the British many valuable lessons about conducting amphibious assaults.  To avoid this vulnerability, they invented machines that could protect them:  “Hobart’s funnies,” tanks that were designed to clear mines and barbed wire, tanks that were armed with flamethrowers, tanks with huge mortars for destroying enemy field fortifications, tanks that could swim ashore on their own power, and armored bulldozers that could help to carry on the work of assault engineers more safely under enemy fire, clearing obstacles on the beaches.  Assault engineers had the unenviable job of clearing all these defenses so that the infantry could get to the enemy.  The British also greatly expanded the role of naval gunfire support and redesigned their tactical air arm so that troops could get more support on the beaches in response to the weaknesses in these arms discovered at Dieppe.  All of these innovations would serve to make D-Day’s beach landing more successful than that at  Dieppe.  

Three examples of Hobart's Funnies in a contemporary museum.  On the left is a Sherman tank fitted out with a dual drive system so it could swim under its own power to the beach.  The middle vehicle is like a DUKW, or 'duck'.  It is a boat until it hits the beach, and then it acts as an armored cat.  The right-hand vehicle is designed to thrash the  ground with the chains on that roller so as to clear a path through minefields.
The Americans had already developed effective landing craft that could reliably bring troops ashore on beaches.  These were called Higgins’ boats, named for their inventor, Andrew Higgins of New Orleans, Louisiana.  (Higgins adapted designs for swamp boats used on the bayous where it was necessary to have very shallow draughts:  A boat that goes too deep into the water gets hung up on lots of obstacles in the swamp.  So, landing craft benefited from riding very high in the water. There is an entire museum devoted to this story in New Orleans that is worth visiting if this topic is of interest).  In 1944, landing craft were a critical bottleneck in the Allied war effort, as these tended to get expended in great numbers in every invasion.  While Operation Overlord was the top priority of the Allies in 1944, landing craft were needed everywhere, including for an invasion of the French Mediterranean coast planned for early August of 1944, and in the Pacific, where they were the mainstay of every US island assault.

Troops disembark from a Higgins boat.  By the time of the Overlord invasion, the Allies had specialty craft for landing tanks, vehicles and supplies, but Higgin's boats were the mainstays of infantry landings.


The Allies had almost three million troops allocated for deployment to the invasion of France, but would only be able to land 160,000 in the initial assault.  After that they would have to build up their forces as quickly as possible. Despite generally adequate shipping, this would prove a very challenging task.  Troops not only needed to be transported, but supplied with every item needed to sustain offensive operations.  Supplies had to be stockpiled in Britain and then loaded and shipped to France, and then would need to be unpacked and distributed to the troops.  Allied innovations include “Mulberries” the code name for a plan to transform the landing beaches into serviceable port facilities; and PLUTO, an underwater pipeline for pumping fuel from Britain to Normandy.  These would begin deployment the moment the landing beaches were secured.

One of the Mulberry pier-heads before it was sunk in position on the beach.  Mulberry components all had to be floated across the English Channel, and then sunk at the Arromanches or Omaha Beach landing sites.
A rare aerial photo of the Omaha Beach Mulberry.  This photo was taken June 12, 1944, just 6 days after troops hit the beach, and a week before the facility was destroyed in a storm.  The Arromanches Mulberry survived the Normandy Campaign, but much of it was later cannibalized when better ports were captured and made operational.

German Defenses:

The Germans had left a sizable occupation force in France after their victory in 1940, and after the Dieppe Raid, they expanded it.  Hitler and Goebbels would brag in radio addresses of the invulnerability of Festung Europa (Fortress Europe), and Germany did devote considerable resources to protecting the French Coast.  On the other hand, in the light of a possible Allied invasion, ensuring the security of French borders was a significant challenge.   In an inspection in 1943 Erwin Rommel realized that although the French ports were well fortified, the beaches were not.  Rommel himself was put in charge of upgrading the defenses.  He found everything he needed -- from troops to concrete, guns, land mines and barbed wire -- were in shorter supply than his requirements due to the immense demands of support for the Eastern Front.  While Rommel’s fifty-eight divisions would greatly outnumber any initial Allied force that could assault the beaches, Rommel didn’t know where they would attack.  He had to defend a 500-mile-long coast because the Allies could land almost anywhere, given their control of the sea and the skies.  Rommel also had to deal with the variability of the quality of the available troops.  These divisions ranged from full strength panzer divisions -- units armed with Germany’s best tanks and crack troops, to fortress garrisons comprised of partially disabled war veterans, under-aged and over-aged soldiers, and ‘Ost’ battalions of captured Poles and Russians who preferred military service to being worked to death in the concentration camps of Eastern Europe.  Many of these troops might not fight effectively in battle.

Field Marshal Erwin Rommel inspecting Festung Europa.  In 1943, it was mostly Nazi propaganda.
Rommel also faced the difficult choice of whether to put his best units -- the armored divisions -- on the beaches or hold them in reserve.  He knew that if he could arrange to meet an Allied attack on the beaches with his heaviest firepower, his forces could crush the landings at the outset.  The problem was that, if he proved incorrect in his guess about where the landings would take place, those top units would be stationed on the wrong beaches and would take longer to move into position to attack those Allied soldiers who made it to shore.  In the end, the decision was taken from Rommel’s hands by Hitler and the High Command, who ordered that the armored formations would be kept in reserve.  Hitler reserved to himself the decision about when to release some of the panzer divisions.  Ironically, this meant that Eisenhower, who would be coordinating the forces of many different nations, would have a unified command and full authority to commit his forces.  Rommel, who commanded only German forces in France, would not have the authority to commit some of his best troops.

Battery Lindeman, which shelled Dover from near Calais.  These made great propaganda photos for the home front, but Rommel had too few massive forts like these, and too much coastline to cover. 
Which Beaches?

The Allies believed that two best locations for the Allied assault on France were the Pas de Calais and Normandy.  The ‘better’ of these, Pas de Calais -- immediately across the Straits of Dover from England -- had many advantages.  It was the most direct route to Germany, closer to the campaign objectives.  It was also at the narrowest point in the English Channel, making the shortest possible trip from English ports to France, and it would be easier to defend from any possible interference by German submarines or patrol craft in the narrower waters.  It was already east of several formidable defensive barriers the Germans could use in their defenses, including the Seine Valley we are sailing now.    The area also held the promise of opening up a number of excellent ports, including Dieppe, Dunkirk and Calais itself, although the Allies did have reliable intelligence suggesting that these were heavily defended.

The other good choice was Normandy.  It was less heavily defended, was relatively easy to cover by air, was close to the major port of Cherbourg,  which might be quickily taken, thereby helping the Allies supply their troops.  Normandy was farther away from the German border, and that might mean that if the Allies could get reinforcements quickly to Normandy, perhaps they could defeat a portion of the German army there before all of the Germans mobile forces could be concentrated.  In their final analysis, invading Normandy seemed to the Allies the best way to prevent 58 from being brought to bear on 8.

The Key Solutions I:  Strategic Air Interdiction

The Allies launched two successful campaigns prior to the invasion that greatly aided in overcoming the German’s initial numerical advantage.  The first was a strategic bombing campaign that targeted bridges, ferries and river transport, railways, railroad marshaling yards, and all manner of transportation resources.  The purpose of this was to inhibit the German’s ability to quickly concentrate their forces in France.  Moving armored divisions by actually driving tanks down the road was slow, inefficient, caused lots of wear on the tanks, and was very hard on the roads.  So anything that made them more difficult to load and transport would mean that the tank divisions would arrive with more broken tanks before the battle on the ground even started and expose them to Allied air attacks as they came to the battle.  This bombing campaign resulted in the destruction of hundreds of bridges, and today you can see the beautiful brand new ones France needed to build after World War II to replace those destroyed in this campaign.  But the bombings also resulted in ‘collateral’ French casualties and damage to other buildings and  to cultural sites.  We saw evidence of this bombing campaign that still remains over 50 years afterward.  But the bombing did have another significant impact: it cleared the skies of Luftwaffe defensive forces.  When the invasion came, enemy fighters and bombers would scarcely make an appearance, because German losses had dictated the withdrawal of such forces for the defense of Germany itself.

 The pre-invasion bombing from the German point of view!


The Key Solutions II:  Psychological Operations:

The second was a campaign of disinformation meant to ‘sell’ the Germans on the idea that the Allies would invade the Pas de Calais.  The intelligence campaign used deception and misdirection including:  planting false papers on the corpse of an Allied officer which implied a Pas de Calais invasion site, then arranging for his body to wash up on the coast of France; withholding General George Patton -- America’s best tank commander, who Germans may well think would be central in any invasion – from the Overlord operation and assigning him to a phantom army poised to invade Pas de Calais.  Fake units, complete with fake barracks and vehicles and phony communications signals were assigned to Patton’s ‘command.’  British intelligence had cracked Germany’s Enigma code system, and German communications using this decryption device were monitored for signs that the Germans were taking the bait.  The Allied bombers left several radar sites in Pas de Calais untouched immediately before the invasion, and on the date of the genuine landings, a fleet of ships was sent to be picked up by this radar to keep the deception convincing right up to the moment the troops were assaulting the Normandy beaches. 

An Enigma machine used to encode secret German radio transmissions.  The capture and decoding of one of these was the Allies' most closely guarded intelligence success of World War II.  In the Normandy Campaign it was mainly used to see if the Germans remained convinced of a Pas de Calais invasion.
This disinformation campaign was very successful, and managed to convince many in the German High Command, including Hitler, that Pas de Calais was the indeed the target.  And that conclusion was probably confirmed for Hitler when his astrologer read the same prediction in the stars!   Hitler was slow to allow the movement of troops from Pas de Calais, for that reason, and the Germans thought for several weeks after the troops had landed that the Normandy invasion was only a diversionary attack.  They were, in fact, so convinced of this that when the invasion occurred, the Pas de Calais ports were so heavily defended that some of them held out until the very end of the war, and important German mobile formations were withheld from the Normandy battle altogether.

The Allied Assault Plan:

The plan called for a beach landing of the assault elements of 5 infantry divisions, two American, two British, and one Canadian.  The three Commonwealth divisions would each be reinforced by a tank brigade, including those fancy vehicles meant to help clear the beach defenses.  The largest air drop yet planned in the war -- two American parachute divisions and one British -- would land on the flanks of the beach to disrupt any efforts the Germans might make to reinforce their defenses on the beaches themselves.  In the critical first hours of the invasion, the Allies could project only 160,000 men against an unknown number of potential defenders.  Everything would depend on getting ashore quickly and then off the beaches to push the defenders back so that the Germans could not shell the landing sites with artillery as reinforcement and supplies were brought in.  

The final Allied plan.  Note that Cherbourg, the good port, is at the end of a peninsula and the US 4th Infantry Division does not need to advance very far to the west to isolate it!  The city of Caen on the east would be easy to defend from German counterattacks, if the British and Canadians can seize it quickly.

Weather:

Of all the variables that Eisenhower could plan for but could not control, the weather was the critical wild card.  There were only brief windows each month in which the moon was full so that airborne forces could see to be dropped properly, and the tide was high enough to clear the German obstacles on the beaches so that the landing craft could get close enough to give the assaulting soldiers the best chances of success.  The first window in May of 1944 came and went:  the Allies were not ready and the weather was too unpredictable to take the risk.  The next chance would come June 5-7, and another would follow June 19-20.  The sooner the Allies could go, the more time they would have in the best campaigning conditions before rain and snow slowed operations in the autumn and winter.  But rain and high winds or choppy seas during these invasion opportunities would make the landings too risky.  The longer the Allies waited, the more opportunity the Germans had to bolster their defenses, and the greater the risk that Allied security would fail and the Germans might correctly assess the landing location.  Allied intelligence thought the Germans were unaware that Normandy was the chosen site, but they couldn’t know for sure whether the Germans appeared to be focusing on Pas de Calais because they were buying the false clues – or because they were engaged in their own disinformation campaign.  If the Germans put their primary strength in the sites where the Allies planned their landings, the Allied invasion was doomed.

The Sum of All Fears:

With all preparations made, the best guess of the Allied High Command was that the assaulting units would take 20% casualties, but 40% was not beyond the realm of real possibility.  In other words, the invasion was expected to cost the Allies as much as 60,000 dead and wounded on the first day.  Furthermore, Allied leaders knew that losses that high could cripple the ability of the remaining troops to function effectively.  They were perfectly aware that most military units ceased to be effective fighting forces when casualties reached that level.  They were betting that the impossibility of retreat would mean that these units would keep fighting, but that assumption was unproven.  

The fate of the three divisions being parachuted on the flanks of the beach was also a concern.   Parachute divisions were elite, highly trained troops but might have to bear the brunt of the counterattacks by veteran German armored units and would not have heavy weaponry to fight them off for very long.   They could only be lightly armed and there was no way to get the tanks, heavy artillery or anti-tank weapons they might need to them by airdrop.   This too was a gamble; there could be no guarantees beyond what solid preparation might provide.  It is easy to appreciate the crushing sense of responsibility Eisenhower felt having to make the command decision to launch the invasion with these expectations.  The deaths of up to 60,000 men gambled against the possibility that the Germans would realize that Normandy was the target site and fortify and garrison it in time to crush the invasion. When the time came to make the call, he would be able to poll the commanders immediately beneath him, but the ultimate authority was his.
Eisenhower reviewing American paratroops immediately before Operation Overlord.