American involvement in the European conflict deepened, this week in the war, as the USA moved ever further from neutrality.

On 10 April 1941, the American destroyer USS Niblack rescued the crew of a Dutch freighter, torpedoed off the coast of Iceland. The Niblack entered the history books by dropping a pattern of depth-charges against the U-boat responsible for the sinking. These were the first ‘shots’ fired between the USA and Germany during World War II. (No blood was drawn. The submarine made good its escape).

The following day, 11 April 1941, Roosevelt extended the American security zone in the Atlantic from Nova Scotia to the Azores. The extension encompassed Newfoundland (then British and the starting point for convoys) and Greenland, and reached almost to the shores of Iceland. Within the new zone, the USA’s warships would protect their merchant shipping. Hitler, for once, avoided confrontation. He ordered his U-boats not to sink American vessels.

But the week was not yet over. Next day, 12 April 1941, US troops landed in Greenland. Then a Danish colony, it became effectively a protectorate of the USA—largely as a result of an agreement that the Danish Ambassador to the United States had bravely signed on 9 April (contrary to the instructions he had received from Denmark, which was under Nazi occupation).

Weather stations based in Greenland were to serve both sides. The Allies used theirs to advantage when predicting weather for the Normandy invasion. The Germans, too, had their (clandestine) weather stations. How these were discovered and put out of action, and the story of the North-East Greenland Sledge Patrol have been told by ex-Royal-Navy officer, David Howarth, in his 1951 book The Sledge Patrol.