Operation Weserübung was the German codename for Nazi Germany's assault on Denmark and Norway during World War II and the opening operation of the Norwegian Campaign. (The term means "Weser Exercise", the Weser being a German river.)

In the early morning of April 9, 1940 — Wesertag ("Weser Day") — Germany invaded Denmark and Norway, ostensibly as a preventive maneuver against a planned (and openly discussed) Franco-British occupation of both these countries; upon arrival envoys of the invading Germans informed both countries' governments that the Wehrmacht had come to "protect the countries' neutrality" against Franco-British aggression. Big differences in geography, location and climate between the two countries made the actual invasions very dissimilar.

The invasion fleet's nominal landing time — Weserzeit ("Weser Hour") — was set to 05:15 AM German time, equivalent to 04:15 Norwegian time.

Contents

1 Background

2 Planning

3 Preliminaries

4 Invasion of Denmark

5 Invasion of Norway

6 Encirclement of Sweden and Finland

7 See also

8 External links

Background

Starting in the spring of 1939, the British Admiralty began to view Scandinavia as a potential theater of war in a future conflict with Germany. The British government was reluctant to engage in another land conflict on the continent that they believed would be a repeat of World War I. So they began considering a blockade strategy in an attempt to weaken Germany indirectly. German industry was heavily dependent on the import of iron ore from the northern Swedish mining district, and much of this ore was shipped through the northern Norwegian port of Narvik. Control of the Norwegian coast would also serve to tighten a blockade against Germany.

In October of 1939 the chief of the German navy, Grand Admiral Erich Raeder, discussed with Hitler the danger posed by eventual British bases in Norway and the possibility of Germany seizing these bases before Britain would. The navy argued that possession of Norway would allow control of the nearby seas and serve as a staging base for future operations against Britain. However, at this time the other branches of the Wehrmacht were not interested, and Hitler had just issued a directive stating that the main effort would be a land offensive through the Low Countries.

Toward the end of November, Winston Churchill, as a new member of the British War Cabinet, proposed the mining of Norwegian waters. This would force the ore transports to travel through the open waters of the North Sea, where the Royal Navy could interdict them. However this proposal was turned down by the dovish Neville Chamberlain and Lord Halifax, due to fear of an adverse reaction among neutral nations such as the United States. After the start of the Winter War between the Soviet Union and Finland in November 1939 had changed the diplomatic situation, Churchill again proposed his mining scheme, but was once more denied.

In December, Britain and France began serious planning for sending aid to Finland. Their plan called for a force to land at Narvik in northern Norway, the main port for Swedish iron ore exports, and to advance across Sweden into Finland. Conveniently, this plan would also allow the allied forces to occupy the Swedish iron ore mining district. The plan received the support of both Chamberlain and Halifax. They were counting on the cooperation of Norway, which would alleviate some of the legal issues. However, stern warnings issued to both Norway and Sweden resulted in strongly negative reactions in both countries. Planning for the expedition continued, but the justification for it was removed when Finland sued for peace in March.

Planning

Convinced of the threat posed by the allies to the iron ore supply, Hitler ordered the German high command (OKW) to begin preliminary planning for an invasion of Norway on 14 December 1939. The preliminary plan was named Studie Nord and only called for one army division.

Between 14 and 19 January the Kriegsmarine developed an expanded version of this plan. They decided upon two key factors. The first was that surprise was essential to reduce the threat of Norwegian resistance (and British intervention). The second was to use the faster German warships, rather than comparatively slow merchant ships, as troop transports. This would allow all targets to be occupied simultaneously, as the transport ships only had limited range. This new plan called for a full army corps, including a mountain division, an airborne division, a motorized rifle brigade, and two infantry divisions. The target objectives of this force were:

The Norwegian capital Oslo and population centers
Bergen
Finnmark
Narvik
Tromsø
Trondheim

The plan also called for the rapid capture of the kings of Denmark and Norway in the hopes that this would trigger a rapid surrender.

On 21 February 1940, command of the operation was given to General von Falkenhorst. He had fought in Finland during World War I and therefore was familiar with arctic warfare. However, he was only to have command of the ground forces, despite Hitler's desire to have a unified command.

The final plan was code-named Operation Weserübung ("Exercise on the Weser") on 27 January, 1940. It would be under the command of XXI Group and include the 3rd Mountain Division and five infantry divisions, none of the latter having yet been tested in battle. The initial echelon would consist of three divisions for the assault, with the remainder to follow in the next wave. Three companies of parachuters would be used to seize airfields. The decision to send also the 2nd Mountain Division was made later.

Initially the plan was to invade Norway and to gain control of Danish airfields by diplomatic means. However, Hitler issued a new directive on 1 March that called for the invasion of both Norway and Denmark. This came at the insistance by the Luftwaffe on the need to capture fighter bases and sites for air-warning stations. The XXXI Corps was formed for the invasion of Denmark, consisting of two infantry divisions and the 11th motorized brigade. The entire operation would be supported by the X Air Corps, consisting of some 1,000 aircraft of various types.

Preliminaries

In February the British destroyer HMS Cossack boarded the German transport ship Altmark while in Norwegian waters, thereby violating Norwegian neutrality, freeing 300 captive British sailors held also in violation of Norwegian neutrality (the Altmark was obliged to released them as soon as she entered neutral territory). Hitler regarded this as a clear sign that Britain was willing to violate Norwegian neutrality, and so became even more strongly committed to the invasion plan.

On 12 March, Britain decided to send an expeditionary force to Norway just as the Winter War was winding down. The expeditionary force began boarding on 13 March, but was recalled and the operation cancelled with the end of the Winter War. Instead the British cabinet voted to procede with the mining operation in Norwegian waters, followed by troop landings.

The first German ships set sail for the invasion on 3 April, and on 8 April a British destroyer began laying the first mines in Norwegian waters. On 9 April the German invasion was underway.

Invasion of Denmark

Strategically, Denmark was relatively unimportant to Germany, except as a staging area for operations in Norway, and of course as a border nation to Germany which would have to be controlled in some way. The country is small and relatively flat, ideal territory for German army operations, and Denmark's small army had little hope of success in armed resistance. Nevertheless, in the early morning hours some Danish regiments engaged the German army, suffering a few dozen dead.

Faced with the explicit threat of the Luftwaffe bombing the civilian population of Copenhagen, the Danish government capitulated almost instantly in exchange for retaining political independence in domestic matters. This resulted in the uniquely lenient Occupation of Denmark, particularly until the summer of 1943, and also in postponing the arrest and deportation of Danish Jews until nearly all of them were warned and on their way to refuge in Sweden. In the end, fewer than 500 Danish Jews were deported, and fewer than 50 of them lost their lives.

Invasion of Norway

Main article: Operation Weserübung Order of Battle

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The German landing sites during the initial phase of Operation Weserübung.

Norway was important to Germany for two primary reasons: as a base for naval units, including U-boats, to harass Allied shipping in the North Atlantic, and to secure shipments of iron-ore from Sweden through the port of Narvik. The long northern coastline was an excellent place to launch U-boat operations into the North Atlantic in order to attack British commerce. Germany was dependent on iron ore from Sweden and was worried, with justification, that the Allies would attempt to disrupt those shipments, 90% of which originated from Narvik.

The invasion of Norway was given to the Army Corps XXI under General Nikolaus von Falkenhorst and consisted of the following main units:

163^rd Infantry Division
69^th Infantry Division
169^th Infantry Division
181^st Infantry Division
214^th Infantry Division
two regiments of the 3^rd Mountain Division

The initial invasion force was transported in several groups by ships of the Kriegsmarine:

Battlecruisers (or fast battleships) Scharnhorst and Gneisenau as distant cover, plus 10 destroyers with 2,000 mountaineering troops under General Eduard Dietl to Narvik;
Heavy cruiser Admiral Hipper and 4 destroyers with 1,700 troops to Trondheim;
Light cruisers Köln and Königsberg, artillery training ship Bremse, transport Karl Peters, 3 torpedo boats and 5 motor torpedo boats with 1,900 troops to Bergen;
Light cruiser Karlsruhe, 3 torpedo boats, 7 motor torpedo boats with 1,100 troops to Kristiansand;
Heavy cruiser Blücher, heavy cruiser (formerly pocket battleship) Lützow, light cruiser Emden, 3 torpedo boats and 8 minesweepers with 2,000 troops to Oslo;
4 minesweepers with 150 troops to Egersund.

A reasonably complete concise description of the invasion of Norway would entail the following (yet to be fleshed out from the outline):

In an act of poetic justice, fate had the German heavy cruiser Blücher sunk in the Oslofjord 9 April 1940, by ancient German Krupp guns (named Moses and Aron, of 280 mm calibre, installed at Oscarsborg Fortress in May 1893) and equally ancient torpedoes:
- German ships sailed up the fjord leading to Oslo, reaching the Drøbak Narrows (Drøbaksundet). In the early morning of 9 April, the gunners at Oscarsborg Fortress fired on the leading ship, the Blücher, which had been illuminated by spotlights at about 0515hrs. Within two hours the ship, unable to manoeuvre in the narrow fjord, was sunk with about 600 men. The now obvious threat from the fortress delayed the rest of the naval invasion group long enough for the Royal family and Parliament to be evacuated, along with the national treasury. The result was that Norway never surrendered to the Germans, leaving the Quisling government illegitimate and permitting Norway to participate as an ally in the war, rather than as a conquered nation.
German airborne troops landed at Oslo airport Fornebu, Kristiansand airport Kjevik, and Stavanger airport Sola — the latter constituting the first paratrooper (Fallschirmjäger) attack in history; coincidentally, among the Luftwaffe pilots landing at Kjevik was Reinhard Heydrich.
Quisling's radio-effected coup d'etat — another first.
Partly thanks to the sinking of the Blücher in the Olso Fjord narrows, the Royal family and Parliament (including government) evaded the German invasion force; King Haakon refused to lay down arms; Clash at Midtskogen; bombs at Nybergsund; Royal family, Parliament, and national gold reserves moved northward ahead of the Germans.
Cities/towns Bergen, Stavanger, Egersund, Kristiansand S, Arendal, Horten, Trondheim and Narvik attacked and occupied within 24 h.
Heroic stand by the Norwegian coastal defense ships Norge and Eidsvoll at Bergen.
First and Second Naval Battle of Narvik (Royal Navy vs Kriegsmarine).
The German force took Narvik and landed the 2,000 mountain infantry, but a British naval counterattack by the old battleship Warspite and a flotilla of destroyers over several days succeeded in sinking all 10 German destroyers once they ran out of fuel and ammunition. The British succeeded in occupying Narvik (with the German mountain troopers retreating into the hills around the town), but subsequently withdrew when Norway capitulated.
Devastating bombing of towns Åndalsnes, Molde, Kristiansund N, Steinkjer, Namsos, Bodø — some of them tactically bombed, some terror-bombed.
Main German land campaign northwards from Oslo with superior equipment; Norwegian soldiers with turn-of-the-century weapons, along with some British and French troops, stop invaders for a time before yielding — first land combat action between British Army and Wehrmacht in WWII.
Land battles at Narvik: Norwegian and Allied (British, French, Polish) success — first tactical victory against the Wehrmacht in WWII — and the following unfortunate withdrawal of the Allied forces (mentioned below); Fighting at Gratangen
The "last stand": Hegra Fortress (Fort Ingstadkleiven) resisted the siege until 5 May -- of Allied propaganda importance, like Narvik.
King Haakon, Crown Prince Olav, and parliament left from Tromsø 7 June (aboard British cruiser HMS Devonshire, bound for UK) to represent Norway in exile (King returned to Oslo exact same date 5 yrs later); Crown Princess Märtha and children, denied asylum in her native Sweden, later left from Petsamo, Finland, to live in exile in the USA.
Norway capitulated on 10 June 1940, two months after Wesertag.

In the far north, Norwegian, French, Polish and British troops fought against the Germans over the control of the Norwegian winter harbour Narvik, important for the export of Swedish iron ore. The Germans evacuated on May 28, but due to the detoriating situation on the European continent, the allied troops were evacuated in Operation Alphabet — and the Germans recaptured Narvik on June 9, by then deserted also by the civilians.

Encirclement of Sweden and Finland

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Iron ore is extracted in Kiruna and Malmberget, and brought by rail to the harbours of Luleå and Narvik.
(Borders as of 1920–1940.)

Operation Weserübung did not include a military assault on (likewise neutral) Sweden — there was no need. By holding Norway, the Danish straits and most of the shores of the Baltic Sea, the Third Reich encircled Sweden from the North, the West and the South — and in the East, there was the Soviet Union, the successor of Sweden's and Finland's arch-enemy Russia, on friendly terms with Hitler under the terms of the Molotov-Ribbentrop Pact.

Sweden's and Finland's trade was totally controlled by the Kriegsmarine. As a consequence, Germany put pressure on neutral Sweden to permit transit of military goods and soldiers on leave. On June 18 an agreement was reached: soldiers were to travel unarmed and not be part of unit movements. A total of 2,140,000 German soldiers, and over 100,000 German military railway carriages, crossed Sweden until this traffic was officially suspended on August 20, 1943.

In August 1940, Finland agreed to grant access to her territory for the Wehrmacht. Initially for transit of troops and military equipment to and from northernmost Norway, but soon also for minor bases along the transit road, that eventually would grow in preparation of Operation Barbarossa.