..From the Weather Gage
The Channel Dash Forecast
LCDR Richard H. Bouchard, USN(Ret).
Big-gun ships, their value in question and their days numbered, advance within gun range of enemy batteries, braving the threat of mines, air and surface attacks. Their endeavor has been well-planned and well-coordinated with the Air Force which provides an almost impenetrable cover. The enemy has had sufficient time to prepare, but is caught unaware. Only the mines and the tides inflict minimal damage as the big ships complete their mission. In the aftermath the enemy is left with recriminations between its air and sea services, but the big ships are essentially through as threats.
The above scenario is not from the Persian Gulf War as USS Missouri and USS Wisconsin conduct their last waltz. No, the scenario takes place almost fifty years before the Persian Gulf War - in the English Channel in February 1942. The "enemies" are the English. And the big-gun ships are the Scharnhorst, Gneisenau, and Prinz Eugen of the German Navy. Their successful "dash" up the channel was due to the German's thorough planning, boldness, and a successful weather forecast.
The battleships1 Scharnhorst and Gneisenau were launched in 1936, each displaced 38,800 tons, and their main armament consisted of nine 11-inch (280mm) guns. The heavy cruiser Prinz Eugen was launched in 1938, displaced 10,000 tons, and carried eight 8-inch (200mm) guns. With the ascendance of air power many of the world's big-gun surface fleets had suffered devastating defeats - the Americans at Pearl Harbor, the Italians at Taranto, and the British off the Malay peninsula had lost the battleship Prince of Wales and battle cruiser Repulse in a forlorn attempt to disrupt the Japanese landing on the Malay peninsula. In response to the loss of Prince of Wales and Repulse, Sir Dudley Pound, Britain's First Sea Lord, enjoined the Navy from bringing capital ships south toward the Channel.2
The German surface fleet had also suffered terrible and embarrassing losses: aggressive action by British cruisers had bottled-up the pocket battleship Graf Spee in Montevideo, Uruguay until its crew scuttled it; more than half of its destroyer force and several cruisers were lost in the 1940 Norwegian campaign; and, the infamous battleship Bismarck had succumbed in 1941 (after leaving the company of the Prinz Eugen. Despite the disrepute that the German leadership held its own surface fleet, the British, duly impressed by the destruction of the battle cruiser Hood3, and perhaps by the ghosts of Jutland4, devoted considerable efforts to destroy or prevent the German surface ships from sortieing. To reinforce this fear, Scharnhorst and Gneisenau had teamed up for two successful sorties - in June 1940 they had sunk the carrier HMS Glorious and its two escort destroyers, and in February and March of 1941, in one of the few successful surface raidings, they sank 115, 000 tons of commerce shipping.
Scharnhorst and Gneisenau had been cooped up in Brest on France's Atlantic coast since returning from their successful March 1941 raiding. They were subjected to almost continuous bombardment and reconnaissance by the Royal Air Force (which had prevented them from joining Bismarck and Prinz Eugen for that ill-fated voyage5). Prinz Eugen joined them in June 1941 after leaving Bismarck to its fate. In light of his surface fleet's poor showing, Hitler decided to concentrate the surface fleet to defend German-occupied Norway and to intercept the supply convoys to the Soviet Union. This would require bringing the Scharnhorst, Gneisenau, and Prinz Eugen from Brest on France's Atlantic coast to Germany via the English Channel6. At stake was 47 percent of Germany's capital ships (by displacement) and the German surface fleet's reputation. For Great Britain its prestige as the world's greatest naval power would be contested in the area it so proudly called - the English Channel.
While Channel Dash has been treated from various angles7 what lends to its attraction for military meteorologists and military planners in general is the intriguing manuscript of Dr. Walther Stöbe 8, Chief Meteorological Officer of Air Fleet 3, based in Paris, charged with making the critical go-no go forecast for the operation. A Luftwaffe meteorologist was making the critical forecast because air cover by the Luftwaffe was considered vital to the success of the operation codename Cerberus9. To maintain air superiority meant to be able to get sufficient aircraft into the air. While the Luftewaffe planned to have bombers, to attack British surface ships, it was the fighter cover to ward off British air power that was deemed crucial. The Luftwaffe requirements were that weather over southeast England prevent or hinder British air operations, such as a low overcast or fog, while ideal takeoff and landing weather prevail over German airfields in France and the Low Countries. However under no circumstances would it be acceptable to have the reverse and allow British aircraft to operate unhindered against the ships.
The Navy also had its own requirements - no fog so that the ships could use their maximum speeds, low sea state so that the German torpedo boats could operate effectively in protecting the ships' flanks, a following wind would help, and finally the sortie would have to take place under maximum duration of darkness which meant in conjunction with a new moon. This would occur during 11 - 17 February. After February, nights would be too short.
Stöbe received his tasking on 4 February 1942 and begin a series of forecasts beginning 5 February through 14 February. At first Stöbe refused to make the forecasts citing the "scientific impossibility." Only after the Chief of Staff reassured him that they were not "nailing the Weather Service down" did Stöbe reluctantly commence his series of forecasts. Stöbe eschewed climatology noting "What good was it to know, for instance, that in February the frequency of weather type 7 . . . was 54 per cent . . . The actual weather can never be approached through such statistical means and frequencies . . . "
Strict security requirements hindered Stöbe's task, he noted that "..few discerning military officers realized during the course of the war that the meteorologist, who in all the important decisions in a modern war may be able to turn the scales, can never correctly prepare his forecast if he is not informed of the tactical plan in time." Because of the strict security requirements, he was unable to use the long-range forecasting expertise of the Central Weather Group10 at Luftwaffe Headquarters in Berlin. This did not greatly disturb him in that he found their routine monthly forecast too general for his exacting task. Because of the joint nature of the operation, he coordinated his forecasts with Dr. Süssenberger, Chief Meteorologist of Naval Group (West) describing the relationship as "..exemplary in very way, which, from the military viewpoint could not always be said of the Air Force and Navy. "
On 6 February, based on the current situation, Stöbe predicted that after the 10th a zone of bad-weather would be expected in southern England, but he acknowledged that critical observations would be needed to confirm that the synoptic situation remained in place. Few observations, mainly signal intercepts, were available from the British Isles. However, a not so secret transmitter at the German embassy in neutral Ireland provided weather reports and also provided one of many points of contention between Ireland and Great Britain11.
The Navy also realized the criticality of the weather forecasts and placed meteorologists aboard the Gneisenau and assigned three of Germany's strategic U-boat assets near Iceland as weather observing stations. Based on the U-boat observations of 9 February, Stöbe identified a developing disturbance which moved unhindered to Jutland. This indicated to Stöbe that small disturbances would continue to move through the area of operations bringing with them the changeable weather situations needed, but more importantly in a predictable sequence ("..expected to show certain constant elements of development and sequence.").The Luftwaffe would task weather reconnaissance for the North Sea to augment the U-boats' reports.
On 10 February Stöbe briefed the impending favorable weather conditions to Admiral Saalwachter, Commander, Naval Group (West); Vice-Admiral Ciliax, commander of the operation for the navy (and a former commanding officer of Scharnhorst); and Fieldmarshall Sperrle, Commander, Air Fleet 3 and his subordinate Colonel Adolph Galland who commanded the all-important fighters. Galland wryly observed: "Now the weather god had to be consulted, for he played an important if not decisive part."12 Admiral Saalwachter scheduled the go-no/go brief for mid-day on the 11th. Early on the11th, the U-boats reported westerly gales and falling pressures indicating the development of another disturbance. Based on the scenario of the previous disturbance noted on the 9th, Stöbe provided his forecast for 12 February:
A low pressure disturbance has formed in the region south of Iceland. Strong winds and falling pressure in the area north of Scotland suggest that in all probability this depression will move south with a speed of 50 km/h and on 12 February between 0800 and 1000 hours will lie in the region of the eastern exit from the Channel and then will move further south.
In the first hours of the forenoon the weather would deteriorate quickly, while the battle area would again clear up. Conditions over the bases would deteriorate as they improved over the battle area. In the afternoon the bases would again have favorable weather. Based upon Stöbe's forecast, Admiral Saalwachter gave the order for the operation to proceed.13
The British anticipating a breakout had setup Operation Fuller to frustrate the ships from reaching safety, but it would be the British who would be frustrated. As with any major fiasco it took a combination of miscues by the British, and good luck and preparation by the Germans14. Ironically the British had an appreciation for the outlook of things when Coastal Command issued the following:
As from the 10th the weather conditions in the Channel would be reasonably favorable for an attempted break through the darkness.
Because of Sir Dudley Pound's prohibition against bringing capital ships south, no"equals" of the three ships challenged them. Undetected until they reached the narrowest point of the Channel, coastal batteries at Dover opened fire without a hit. The rain squalls reduced visibilities and obscured the ships so that the batteries could not spot their splashes and correct their aim. With the alert given so late only a series of heroic, but hopeless torpedo attacks could be mounted by motor torpedo boats, biplanes, and World War I-vintage destroyers which resulted in no hits15. The last British attacks came as the German ships escaped unscathed into mists, rain squalls, raging seas and darkness.
The German ships made good time moving over 30 knots helped by the currents of over 2 knots which set to the northeast during their passage of the Channel16 and the good visibility which allowed them to safely navigate at those speeds. The tides played a crucial role because of the need to have sufficient depth for safe navigation and to provide sufficient clearance from mines, as the route was swept for mines to a depth of 12 meters. The naval planners also had access to a needed "forecast" in the form of tidal current predictions freshly compiled by the Marine Observatory in Wilhemshaven17. During the night of 11-12 February winds were light and visibility very good in the high pressure area over the western English Channel. By morning on the 12th, winds had increased out of the southwest ahead of the approaching front which also aided the ships in their passage. Because of the late warning, attacks did not commence until afternoon when the weather deteriorated with the approach of the front. The only casualties to the great ships were caused by mines (Scharnhorst, twice and Gneisenau, once) and the Germans lost two patrol boats, and they were able to continue to Wilhelmshaven. Ironically despite the thoroughness of the German preparations, no pilots or tugs were waiting to take the ships into their new homeports. As Gneisenau waited, strong tides pushed the ship onto submerged wreck. Only Prinz Eugen would reach port unscathed contributing to its reputation as a "Lucky Ship"18
The London Times would headline: "Vice-Admiral Ciliax had succeeded where the Duke of Medina-Sidonia failed. Nothing more mortifying to the pride of our seapower has happened since the seventeenth century."19 There would be antagonisms between the air and sea services over who was to blame20 and while official investigations found much blame to go around, the ensuing wartime security clamp on the report would result in a public whitewash of the incident. But in the minds of English it would even rankle more than the capitulation of Singapore with the surrender of 100,000 troops21. But the head of the German Navy, Grand Admiral Raeder would recognize the removal of the ships from the Atlantic to the North Sea-Baltic not as a tactical victory, but a defeat22. Raeder would eventually quit, to be replaced by U-boat Commander Doenitz, after enduring one of Hitler's tirades following another failure by the surface fleet.
Vice-Admiral Ciliax would conclude in his report that the weather was not decisive and indeed was an advantage to the enemy. His point of view being that the reduced visibilities during the Dash allowed British attackers to approach to closer ranges before being detected by his forces. However he was not privy to the effect of the weather on British air operations. Because the British naval forces assigned to Fuller were woefully inadequate, it was the air operations that really had any hope for success. Because of the weather, RAF Bomber Command was not at full alert as it expected a quiet day of the war23, and because of the low ceilings the bombers could not see their targets from a sufficient altitude for the bombs to pierce the ships' armor. Bomber Command had 340 aircraft available for attacks, but many bombers were launched with general purpose bombs to harass rather than destroy the ships. Very few bombers actually found the ships because of the low ceilings and visibilities. None scored hits.
In contrast to Ciliax, Grand Admiral Raeder, Commander-in-Chief of the German Navy, who vigorously opposed the Channel Dash as it would remove their strategic value, concluded the weather as favorable for the Germans.24 Colonel Adolph Galland, who commanded the fighters, found the weather more favorable for the German Navy than the Luftwaffe and observed that "..the weather actually occurred as forecast, even if it was about from six to eight hours late. But it saved us."25
In another instance a squadron of RAF Coastal Command torpedo planes brought down from northern Britain could not land at any airfields with torpedo depots because of the weather. After torpedoes were trucked in (very slowly over icy roads) the aircraft headed out to sea late in the day, and became separated. One group of planes attacked the Germans to no avail and another group attacked the returning British destroyers - luckily with the same lack of success as with the German ships.
The RAF would prevent Gneisenau from ever sortieing again. Finally in March 1945 she was towed to Gydnia, Poland and scuttled as block ship. Prinz Eugen would surrender to the Americans and end up as part of the Bikini atomic bomb tests. The ship would remain afloat after two tests and was finally towed to Kwajelain in the Marshall Islands and beached on San Carlos Island26.
Weather would have a role in the Scharnhorst's remaining operations including its demise. On 9 September 1943, Scharnhorst joined the Bismarck's sister-ship Tirpitz in an attack on the allied weather station on Spitzbergen Island. This operation would be Tirpitz's only engagement to fire its 15-inch guns offensively and would be Tirpitz's last operation.27
Later, the mistaken belief that Tirpitz and Scharnhorst were approaching the Russian-bound convoy PQ17 so unnerved the British admiralty (Sir Pound, again) that they ordered the convoy and its escorts to scatter.28 Ten ships of the convoy carrying over 100,000 tons of supples fell victim not to Scharnhorst or Tirpitz, but to U-boat and air attacks.
In retribution, Scharnhorst would fall victim to a British trap in which weather was a contributing factor. The British had expected Scharnhorst to sortie against a convoy and had deployed two squadrons of ships to lie in wait. However, upon leaving the shelter of the Norwegian bay, seas were too great for the escorting German destroyers, Admiral Bey (a "destroyerman"who had commanded the destroyers during the Channel Dash) sent a radio message to headquarters asking if the operation should be canceled. The reply would be negative. The German destroyers returned to port, and Scharnhorst proceeded alone to intercept the convoy, but the radio message was intercepted by the British who closed the trap, unhindered by a German destroyer screen, and sent the Scharnhorst to its final resting place in a torrent of torpedoes and shells on 26 December 1943 in the Battle of North Cape.
The success of operation Cerberus/Donnerkiel rests on the daring plan and joint coordination, but instrumental to its success was the forecast by Stöbe and the weather's role in concealing the German ships from detection or employing more armor piercing bombs. Also contributing to the success was planning around the need that successful forecast that can be held true today:
- Understanding by the operational commanders of the importance of the weather support to the success of the operation include dedicating resources to the crucial weather observations,
- Well-articulated and timely requirements which contribute to the alertness and understanding by the meteorologist for the tactical situation,
- A succinct and tactically-tailored forecast,
- Avoidance of slavishness to climatology, and
- Cooperation with other services.
1. The Royal Navy referred to these ships battle cruisers (schlacktkreuser) because they sacrificed gun size (11-inch vice 14 inches or more for modern battleships) rather than armor for speed, but the Germans referred to them as battleships (schlacktschiffe). See Jak P. Mallaman Showell, The German Navy in World War II, (Annapolis, MD: Naval Institute Press, 1979), p. 105.
2. John Deane Potter, Fiasco, Stein and Day, 1970, p.43. Potter provides more personal narratives than Kemp (8).
3. Bismarck is generally credited with the destruction of Hood. However, a case can be made for Prinz Eugen. See Ron Vielicka, Blut Und Eisen: Did Prinz Eugen Sink The Hood?, Germany's Big-Gun Navy At War, Sea War Special v.2 (1), 1995, pp. 42-51.
4. The British lost three battle cruisers and three heavy cruisers. Arthur J. Marder, From the Dreadnought to Scapa Flow, v. 3, Oxford University Press, 1978, p. 255.
5. Graham Rhys-Jones, The Loss of the Bismarck: Who Was to Blame?, Naval War College Review, v. XLV, no. 1, Winter 1992, p. 30.
6. A plot of the route can be seen at http://www.home.gc-system.de/emmerich/m5.htm (link is broken, will try to locate it's new URL)
7. Among them is an Operational Security (OPSEC) training film listed at http://www.ecip.com/misac/opsec.htm and http://www.opsec.org/associations/IOSSOrder.html . Also Bill Riddle has posted some information about the Electronic Warfare aspects of the Channel Dash.
8. Walther Stöbe, Forecasting for the Escape of the Scharnhorst and Gneisenau, The Meteorological Magazine, v. 127, no. 1276, November 1978, pp. 321-338.
9. Cerberus is the three-headed dog of Greek mythology who guards the entrance to Hades. Stöbe calls the operation Donnerkiel (Thunderbolt) which referred to the Luftwaffe's part of the overall Operation Cerberus.
10. This may have been a blessing in disguise, for the CWG (or Z-W-G, in German) had issued a long-range forecast for the 1941-42 winter in Eastern Europe, the "Russian Front", which called for a normal or mild winter. It would turn out to be one of the coldest on record. The German troops within 30 km of Moscow were unprepared for the cold - lacking winter clothes and properly conditioned mechanical equipment. A Russian offensive of early December would halt the German advance on Moscow. The meteorologist who issued the forecast when told of the persistent low-temperatures stated: ".. the observations must be wrong!" See J. Neumann and N. Flohn, Great Historical Events That Were Significantly Affected by the Weather: Part 8, Germany's War on the Soviet Union, 1941-45. I. Long-range Weather Forecasts for 1941-42 and Climatological Studies, Bulletin of the American Meteorological Society, v.68(6), June 1987, pp. 620-630. CWG would redeem itself with the crucial Battle of the Bulge forecasts, see Werner Schwerdtfeger, The last two years of Z-W-G, Weather, 41: Part 1, pp.129-133; Part 2, pp.157-161; and, Part 3, pp. 187-191.
11. Tim Pat Coogan, Valera: The Man Who Was Ireland (New York: Harper, 1996), pp. 600-601.
12. Adolph Galland, The First and the Last (London, UK: Methuen and Co., 1955), p. 151.
13. Stöbe relates that on the 10th Saalwalter revealed he was determined to proceed on the 12th because the 13th was a Friday and "No man of the Navy would give the operation a chance on such a doubly ominous day."
14. For details see Peter Kemp, The Escape of the Scharnhorst and Gneisenau,(Annapolis, MD: Naval Institute Press, 1975). Kemp provides more detail than Potter (2).
15. Peter C. Smith, Hold The Narrow Sea: Naval Warfare in the English Channel 1939-1945, (Annapolis, MD: Naval Institute Press, 1984), pp. 145-154.
16. Tidal current predictions in the English Channel are based on the time of high tide at Dover. The ships left Brest at 2045 GMT on the 11th about one hour after Dover high water (DHW). (The Admiralty Tide Tables, Part I. Tidal Predictions for the Year 1942, Section A. Home Waters, (London, UK: Hydrographic Department, Admiralty, 1941), p. 16.). Between Dover high water and one hour after, the current off the Brittany peninsula changes from a southwest to a northeast set. The tidal surge advances reaching the Cotentin peninsula at 6 hours after Dover high water and reaches Dover about one hour before DHW (from Michael Reeve-Fowkes, Stanford's Tidal Atlas English Channel West (London, UK: Stanford Maritime Limited, 1976). The ships reached Dover about 1215 GMT on the 12th which was about four hours after DHW which occurred at 0825 GMT on the 12th. This would be the last hour for northeastward set of the current in the Straits of Dover (from Oberkommando der Kriegsmarine, Karten der Gezeitenströme für die Strasse von Dover (Wilhelmshaven, GE: Marine Observatorium, 1940), Tafel 10, 11, and 12).
17. Potter, pp. 62-63. The German navigators probably used:
Oberkommando der Kriegsmarine, Karten der Gezeitenströme für die Strasse von Dover, Karten der Gezeitenströme für das Gebiet des Kanals, Östlicher Teil, and Karten der Gezeitenströme für das Gebiet des Kanal, Westlicher Teil. All three (Wilhelmshaven, GE: Marine Observatorium, 1940) and in the collection of the Maury Library, Stennis Space Center, MS.
18. P. C. Coker III, The Prinz Eugen - A Lucky Ship, Naval History, V. 3(3), Summer 1989, pp. 30-31.
19. Cited by Dan van der Vat, The Atlantic Campaign: World War II's Great Struggle At Sea, Harper and Row, 1988, p. 74. The Duke of Medina-Sidona led the Spanish Armada. In 1667 the Dutch Admiral De Ruyter sailed up a river in England, attacked the English fleet at anchor, and stole the flagship.
20. John Keegan, The Second World War, Penguin Books, 1988, p. 113.
21. Winston Churchill, The Second World War: The Hinge of Fate, (Boston, MA: Houghton Mifflin Co., 1950), p. 81.
22. Nathan Miller, War At Sea, (New York, NY: Scribner, 1995), p. 302.
23. Terence Robertson, Channel Dash, (New York, NY: Dutton, 1958), p. 153.
24. Erich Raeder, My Life (Annapolis, MD: United States Naval Institute, 1960), p. 361.
25. Galland, p.151.
26. P. C. Coker III, p. 32.
27. William H. Langeberg, The German Battleship Tirpitz: A Strategic Warship?, Naval War College Review, v. XXIV, no. 4, July-August 1981, p. 87.
28. van der Vat, p. 285.