Birger Stromsheim was one of the Norwegian team that helped to thwart Nazi attempts to construct an atomic bomb. With five of his countrymen, Stromsheim was parachuted in February 1943 into the Telemark region of southern Norway.
Trained by the Special Operations Executive (SOE), their mission was to blow up the Vemork Norsk hydro plant, in Rjukan. The facility produced the heavy water, or deuterium oxide, and was key to Nazi hopes of mastering the atomic chain reaction which would lead to a nuclear bomb.
The mission was code-named Operation Gunnerside and included four other Norwegian agents already in the country. The combined team launched their assault, on the night of 27 February 1943. An earlier mission to destroy the facility in 1942, code-named Operation Freshman, had ended in tragedy when four Norwegian commandos formed an advance team for 34 Royal Engineers. Bad weather caused crashes when the British were dropped into the target area in two Horsa gliders. Their orders were to destroy the plant and then make their escape to neutral Sweden. In fact, some of them were killed instantly, 14 survivors were captured and, although in British uniforms, were shot in accordance with Hitler’s notorious “commando order”.
On this occasion the team, led by 23-year-old lieutenant Joachim Rønneberg, included two other officers, and three NCOs, among them Stromsheim who, aged 31, was the oldest. Ronneberg later acknowledged that he looked up to sergeant Stromsheim, who was one of four explosives experts and a skilled skier who spoke good English and German. They faced a daunting task. Since Freshman the Germans had increased security at the plant with mines, floodlights, and more guards.
In any case, the terrain made the defences seem well-nigh impossible to breach. The plant was built on a thickly forested ravine, with Germans guarding the bridge that led to its entrance. It was decided that the team would climb down one side of the ravine, cross the icy River Maan, and make their way up the other side, following a railway track that led into the plant. They were helped a little by the bad weather which put the Germans off their guard.
Getting into the plant was as challenging. Ronneberg first tried through a basement door, without success. The brief from London had advised them to climb a stairway to a hole in the wall for the cable, and to follow the cable tunnel running below the ceiling of the ground floor of the plant. Ronneberg and Hans Storhaug entered in this way and took the guard by surprise. Stromsheim and two others broke a window to get in, but the German guards heard nothing above the powerful drone of the generators.
“Two of us mounted the explosive charges. The fuses were about two minutes long. I cut them down to 30 seconds and lit them,” Ronneberg explained. They were able to escape rapidly because he had a key. “The German guards had been put out of action, locked up in the guardhouse.”
Operation Gunnerside was considered successful. The entire stock of heavy water produced during the German occupation, over 500kg, was destroyed, along with equipment critical to operation of the electrolysis chambers. Although 3,000 German soldiers were dispatched to search the area for the commandos, all of them escaped; five of them skied 250 miles in snowstorms to Sweden, two proceeded to Oslo, where they helped by the underground, and four remained for further work with the resistance.
Birger Stromsheim was born in the Norwegian port of Aalesund and worked as a builder before the war. He and his wife Aase escaped by boat to the Shetlands in September 1941, to join the anti-Nazi resistance. Stromsheim was awarded the British Military Medal; the Norwegian St Olav Medal; the US Medal of Freedom; and the French Legion of Honour and Croix de Guerre.
Their exploits were dramatised in the film The Heroes of Telemark (1965), starring Kirk Douglas and Richard Harris, which was criticised for departing from the facts and did not mention Stromsheim. In a later documentary, The Real Heroes of Telemark, which cleaved more closely to the truth, Stromsheim was interviewed. The story was also covered in the 1948 Franco-Norwegian film Kampen om tungtvannet, in which many of the original Norwegian commandos starred as themselves.
Birger Edwin Martin Stromsheim, commando: born Aalesund, Norway 11 October 1911; died Oslo, Norway 10 November 2012.