Shortly after D-Day the heaviest storm lashed through the English Channel, on 19 June 1944, which meteorology did not expected, reckons, or is able to explain until now!

Posted: July 03, 2019
Add 1 – Extract: Ch. C. Bates about D-Day and “the Big Storm, 19-22 June 1944”

Only 13 days after landing troops on the shores in Normandy on 06 June 1944, an unexpected storm lashed across the English

Ships transition on most severe storm


Channel on 19 June 1944 lasting three days. From Britain to France the operation and supply area for the invasion was severely affected. 800 ships and floating units were beached or lost, more than the German army managed to take out during the entire campaign. It was claimed that this was the most severe storm in June for 40 years.

 The weather maps do not show the event. The Met services did not foresee the event, and modern science is still speechless; no interest, no research, no explanation. That should not be accepted any longer, as the event is presumably a perfect example what sudden excessive activities at sea can do to regional weather, in a sense that it may have significantly increased the windy weather. During the days before June 19th the water body of the English Channel had been revolved in an unprecedented manner, by transport, naval control, gun fire, bombing, depth charging, and sinking ships. That is just the subject that weather can be made, and meteorology should at least be willing to learn from such events.

 Climate map from the 25th June 1944   06 June 1944Climate map from the 6th June 1944


The landing of Allied Troops on the shores of Normandy in France on the morning of the 6th of June 1944.  It was one of the most decisive turning points during WWII to defeat Germany within the next 10 months. Certainly the weather forecast was crucial. US and British weather units did it separately and often very controversial. However on D-Day the weather turned not against the landing operation, which initially involved more than 150’000 men and 7’000 ships, 1’200 naval vessels, 850 merchant ships, and about 5’000 transport units as landing or ancillary crafts. The British Met-Office claims that its service is a major landmark in their history with the annotation


 “The weather was crucial to the Allied Forces’s success for D-Day landings in June 1944. General Eisenhower’s chief meteorologist, Group Captain John Stagg, a Met Office forecaster, advised of a narrow ‘weather window’ for the operation to go ahead: “probably the only day during the month of June on which the operations could have been launched,” President Truman later said.”

Luckily the weather did not hamper commencement of the invasion according to long-term planning, so there is no need to come up with a judgement whether the weather men had been of service as claimed. But as they failed to forecast a severe storm only two weeks later, the skill may not have been as high as they wish others to assume.    Fig .below – left 


Weather map Wheater map detailed

Weather maps and Sea activities

One can only wonder that researchers have been so reluctant to investigate the weather situation around June 19th, 1944 and where the great storm came from. The weather maps indicate nothing exceptional. The air pressure over the English Channel is with 1020 hPa fine, and the pressure difference between Scotland   (1025) and North Italy (1005) is hardly anything that generates strong wind pattern. Nowhere over the North Atlantic loomed one or two storm centers as on D-Day. 

 Climate map from the 4th June 1944  Climate map from the 5th June 1944  Climate map from the 6th June 1944


 Climate map from the 19th June 1944 - Bodendruck (hPa)  Climate map from the 20th June 1944 - Bodendruck (hPa)  Climate map from the 21st June 1944 - Bodendruck (hPa)

But what is difficult to assess are the uncountable activities above and under the sea surface in the ocean region from Ireland to the southern Biscayan and along the entire English Channel to Dover . In the two weeks after D-Day the Allies constructed two artificial harbours out of 600,000 tons of concrete between 33 jetties within just 3 days, and had 15 km of floating roadways for the discharge of men and vehicles.  The US troops build “Mulberry A” at Omaha Beach; the British “Mulberry B” at Arromanches (later called Port Winston) respectively. Before June 19th,  the Allies could use the installation to land about 500’000 men, 100’000 vehicles, and 400’000 tons supplies.

Although the landing operation itself was impressive, the sea area from the West of the English Channel to Dover was packed with ship operation for transport and military actions as well. The Allies employed more than 1’200 naval ships, the Germans another 200. In addition the Germans started to evacuate their naval bases at Cherbourg, Le Havre, Brest, either to fight the enemy, or to move ship, persons and material to safer ports in Norway or Germany. Many thousand sea mines are dropped form ships and bombers, and bombing missions flown. There was ship to ship, or ship to air bomber, or shore to ship shelling many hundred times per day.

From D-Day to the 19th June the sea in a wider area of the Normandy shores was churned and turned up-side-down. The sea surface got colder. Sun warmed water was exchanged with deeper and colder water, while the mid June sun supplied a lot of sun ray to the surrounding land masses. That presumably build the ingredients for the making of a devastating storm which start on June 19 and lasted for three days by which the “Mulberry A” port at Omaha Beach was so completely wracked that its further use was abandoned, while the damage at “Mulberry B” could be repaired fairly soon. 


Climate map from the 18th June 1944 Climate map from the 21st June 1944
Climate map from the 22nd June 1944 Ships from D-Day on 6th of June 1944 in World War

No concern. No interest. No lesson learned.   

A unique weather event occurs at the most crucial military operation of all time, but atmospheric science is silent. There was Crossing the English Channel on D-Day on 6th June 1944no interest than, nor during the last decades to shed any light on the event, why it had not been observed in advance, what caused it, and why did it last for three days in a months which is not known for its storminess. The event caused enormous losses, and severely hampered military operation, which meteorology services seem not interested to see. One should call this ignorance and behaviour irresponsible. To ‘move on’ immediately after the Great Storm might be understandable in June 1944, but completely unacceptable since the debate on climate change started two decades ago. That would not only be required for historical reason, but to ensure that weather and climate  research does not fail to investigate well observed events that could tell a lot of the weather system, and whether man can influence weather-making by activities in the marine environment within a couple of days.

If the Met Office is so proud on its service with regard to D-Day weather forecast, it should be ashamed that the most severe storm for 40 years in the English Channel, from June 19-21, is still not fully assessed, investigated, and thoroughly explained. 

Addendum 1

Charles C. Bates Lieutenant Colonel , U.S. Air Force (Retired) ( USA , 2010)
Sea, Swell and Surf  Forecasting  for D-Day and Beyond
The Anglo-American Effort, 1943-1945

FULL 38 page long PDF.

 Extracts from page 1 to 18 – Invasion Planning

Page 12 
(planning stage): …….Admiral Ramsay knew it would be impossible to control from London an invasion fleet of 1,213 naval combatants, 4,126 landing craft/ships, 736 naval auxiliaries, and 864 merchant vessels.  …..

Pager 15 
….General Eisenhower made the tense situation worse during Friday, June 2. With the proposed D-Day just three days away, “Ike” advised Stagg that he now required weather briefings during both morning and evening hours. ……..
…… the majority’s prognosis that the proposed D-Day of June 5would feature rain, high seas, and low clouds within the assault area. Then, after listening to this updated forecast, as of 0430 DBST Eisenhower ordered this massive invasion involving 500,000 personnel postponed for 24 hours. …..

Page 16
….Then at noontime stations on Ireland’s west coast reported a major cold front moving eastwards at 30 knots that was certain to pass through the Normandy assault area during early Monday, June 5. …….

 Page 18 to 20
Wave Forecasting for the “Big Storm” (19-22 June 1944)
The section is reprinted in full  

Following June 6th,  Section activities were quiescent for the next 11 days with one exception. During D-plus-8 (14 June 1944), Lt. Crowell reported for duty complaining of shrapnel rattling around his wash basin in Half Moon Street because of low-flying German aircraft during the night. These aircraft, of course, were the pesky “doodle­ bugs” with 850 kilogram (1,870 pound) warheads that soon would be impacting Greater London an average 80 times per day. Even so, denizens of the Citadel had nothing to fear for their windowless structure was capped with 20 feet of concrete. Unknown to us, however, was the War Office’s ongoing use of 600,000 tons of the same material for building artificial harbors off the OMAHA and GOLD beachheads by D-plus-21 (27 June 1944).  

Termed a “MULBERRY,” such a harbor would be approximately the size of Dover Harbor and enclose a square mile of beach front featuring a 21 foot change in sea level during spring tides. On the deep water side, three lines of barriers would suppress incoming waves. Furthest out were a row of Admiralty-designed BOMBARDONS

comprised of 24 free-floating but anchored steel cruciform with a 19 foot draft. At mid­ point and firmly emplaced in a low tide water depth of 30 feet were 26 PHOENIXs consisting of massive free flooding concrete caissons each 200 feet in length. Then close in for the protection of small craft were “CORNCOBS,” a string of antiquated ships intentionally scuttled into 10 feet of water at low tide. Finally, for rapid ship-to-shore transfers several miles of floating roadways extended out to Lobnitz pier-heads that moved upwards or downwards with the tide level. As for a MULBERRY’s ability to withstand wave action, its prime designer, Brigadier Bruce White, CBE, RE, assumed it would stay intact throughout a conventional summer storm featuring Beaufort Force 6 winds (approximately 24 knots) (White, 1980).  

All told, 35 convoys moving as slowly as 3 knots were required to bring the MULBERRY paraphernalia across the Channel. Scheduling such convoys fell within the purview of Admiral Ramsay. Accordingly, Commander Fleming noted later:

It was decided that the most important convoy of all carrying very large quantities of essential heavy equipment should, if possible, be held back until there were prospects of a period of 48 hours with little or no wind and calm seas. By 17th June (D plus 11), it appeared that ideal conditions would prevail for the next two or three days …. On the strength of my forecast to this effect, the [100 tug] convoy was ordered to sail on 18th June.

 Unfortunately, at this very time, both Fleming and Stagg’s SHAEF team of meteorologists fell into a “sucker’s hole.” Based on prior episodes, they predicted a lobe of 1,030 millibars pressure would extend northeastwards from the Azores into the English Channel area, thereby allowing calm seas. Instead this lobe’s center paused near southern Ireland while a low pressure zone moved up from southern France . Consequently, from June 19th through June 22 near gale force winds blew from the northwest directly down the Channel for 120 miles. Thus, Ramsay’s special convoy became a total wreck. Fleming further remembers:

“If previously I had never experienced sheer misery, I certainly did now, and the fact that I was living in close contact with those responsible for ordering the operation was as salt in my wounds … the feel that one had been, however inadvertently, the main contributor to what was almost a major disaster is something not easily put aside.”

 Because the onset of the storm was not predicted, pandemonium reigned throughout the beachheads. Fortunately, north-westerly winds offered only a glancing blow to the British sector so its MULBERRY-B, now called Port Winston, and associated small craft suffered only moderate damage. Off OMAHA , however, aboard the U.S. flagship USS AUGUSTA, Commander Steere was reporting maximum wave heights of 12 feet and wind gusts up to 32 knots. Inshore, chaos. With inadequate holding tackle, 800 landing craft collided with each other or stranded on the beach. Early on, five break­ away LCTs hit the floating roadways and caused them to buckle badly, thereby dooming the pier-heads from future use. Even worse, the 200-foot long BOMBARDONs broke loose and struck the embedded PHOENIXs, damaging 21 out of 31 of those vital block-ships beyond repair.  

At the time, it did not seem possible but all storms must end. In anticipation, during the mid-afternoon of June 21st (D-plus-lS), Portsmouth ‘s convoy dispatcher called Admiralty for advice as to when beachhead surf heights would drop to a tolerable level, i.e., to four feet or lower. As the wave specialist on duty, the author indicated 24 hours hence. In the storm’s aftermath, after inspecting the American’s MULBERRY-A, Rear Admiral Kirk recommended its abandonment. During 2 July 1944 (D-plus 26), General Eisenhower concurred even though Cherbourg was still nearly useless and Breton’s ports of Brest , St. Nazaire, and Lorient were far from being captured. In other words, the requisite 20,000 tons of daily supplies for what was now the 1st and 3rd U.S. Armies must continue primarily arriving over the beachheads.  

Entire 38 page long PDF.

First posted : April 2010 
Revised text from: 17. June 2013 (co_7-4)

More  publications

D-Day and Geography
By: Mildred Berman
Geographical Review, Vol. 84, No. 4 (Oct., 1994), pp. 469-475
American Geographical Society


Simulation of Normandy Invasion on 6th of June, 1944
By: John Vassie and Byung Ho Choi
Journal of Coastal Research, Special Issue No. 85: Proceedings of the 15th International Coastal Symposium, Haeundae, Busan, 13-18 May 2018 (2018), pp. 1071-1075
Coastal Education & Research Foundation, Inc.

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