World War II Day by Day

Washington, D.C. • April 10, 1941

On April 9, 1941, a full year after Operation Weser­uebung had brought Den­mark and Nor­way into Nazi Germany’s orbit, the Danish ambas­sador in Wash­ing­ton, D.C., Hen­rik Kauff­mann, signed an execu­tive agree­ment with the U.S. Secre­tary of State, Cordell Hull, autho­rizing the U.S. to protect the remote Danish colony of Green­land “against attack by a non-Amer­i­can power” and to con­struct mili­tary sta­tions on the is­land for that pur­pose. (Green­land, popu­lated then by 18,000 native Iniut and less than 500 Danes, is separated from Canada’s Elles­mere Island to the north by only 16 miles.) The Danish envoy, not­able for refusing to recog­nize the Nazi occu­pa­tion of his coun­try, was sup­ported in his move by Dan­ish diplo­mats in the U.S.

Kauffmann was also supported by Danish autho­rities in Green­land, who were keenly aware of the diffi­culties the mother country faced in governing the island. After Germany’s occu­pa­tion of their country, Danish author­ities in Green­land’s admin­is­tra­tive capital at Godt­haab (today’s Nuuk) declared the island to be a self-ruling terri­tory under a 1925 Danish emer­gency law. After debating among them­selves, they agreed to recog­nize Kauff­mann as their repre­sen­ta­tive in Wash­ing­ton. By signing the U.S. treaty “in the name of the King,” Kauff­mann ignored instruc­tions from his home govern­ment and acted in clear vio­la­tion of his diplo­ma­tic powers. Indeed, the treaty, while affirming Green­land’s loyalty to Denmark, was disavowed by author­ities in Copen­hagen in part because it allowed the U.S. to estab­lish naval and air bases on Danish terri­tory. (Although occupied by German armed forces, Denmark still regarded itself a neutral coun­try.) The Danish govern­ment even­tually charged Kauff­mann with treason for his inde­pen­dent poli­tical moves. (After the war the Danish Parlia­ment revoked Kauff­mann’s treason sentence and legalized U.S. military installations in Greenland.)

On this date, April 10, 1941, one day after the signing cere­mony, Presi­dent Frank­lin D. Roose­velt played his trump card by declaring Green­land to be part of the West­ern Hemi­sphere. This decla­ra­tion brought Green­land under the pro­vi­sions of the Mon­roe Doc­trine, which U.S. presi­dents had used to oppose Euro­pean inter­fer­ence in the Americas for over a century. The inclu­sion of Green­land into what the U.S. con­sid­ered its exclu­sive play­ground and the estab­lish­ment of bilateral diplo­matic rela­tions in May was all the more im­por­tant after Germany had made recon­nais­sance flights over Green­land, causing concern in Wash­ing­ton circles that Adolf Hitler might try to estab­lish bases on the island for future use against the U.S. (See below, “Green­land’s Role in the ‘Weather War’.”) Green­land’s occu­pa­tion by Amer­i­can armed forces on the same day as the announce­ment was followed two months later by the occu­pa­tion of the stra­te­gically located Danish depend­ency of Ice­land in the mid-Atlantic, where U.S. Marines supple­mented and even­tu­ally replaced British and Cana­dian service members who had been stationed there since May 10, 1940.

The occupation of Greenland and Iceland brought the Roose­velt ad­min­is­tra­tion closer to sup­porting Great Britain in its Battle of the Atlantic. Hence­forth, U.S. Navy ves­sels extended their con­voy patrols to these two terri­tories, both lying along the sea lanes linking the U.S. to its future ally against Nazi Germany.

Greenland’s Role in the “Weather War”

Left: Predicting the weather became an integral part of World War II intel­li­gence gathering. Infor­ma­tion on the weather was vital for plan­ning and exe­cuting mili­tary oper­a­tions for both bel­lig­er­ent sides. For their part, the West­ern Allies mutually agreed to censor them­selves in open radio trans­mis­sions when reporting compre­hen­sive weather data (pres­sure, wind, tem­per­a­ture, etc.) that could be of value to Nazi Germany. From their base in occupied Norway, the Germans for their part set up four secret weather sta­tions on Green­land’s mete­o­rol­o­gically strate­gic east­ern shore. A special weather-recon­nais­sance unit of the Luftwaffe, the Gross­raum Wetter­erkundungs­staffel—Wekusta for short—flew in supplies. The stations were intended to pro­vide the Wehr­macht (German armed forces) with advance weather infor­ma­tion for the dual pur­pose of assisting their sub­marine, sur­face, and air cam­paign against Allied mer­chant shipping transiting the North Atlan­tic between North America and Great Britain and pre­dicting the weather situ­a­tion in the Euro­pean Thea­ter as much as 72 hours in advance. (The Germans—actually the armed U‑boat crew of U‑537 on its first patrol—briefly estab­lished a remote auto­matic weather sta­tion, Weather Station Kurt, in Martin Bay on the north­ern tip of Lab­ra­dor, New­found­land, on the North Amer­i­can con­ti­nent in October 1943 and another one,  Schatz­graber (“Trea­sure Hunter”), in the Soviet (Russian) Arctic from 1942 to July 1944 on remote Alex­an­dra Land Island, the western­most island of the Franz Josef Archi­pel­ago, which researchers uncov­ered only in 2016.) From their own weather stations in Green­land the Allies gathered weather data to plan their invasion of Normandy, France, in June 1944. As poor as the photo in the left frame is, it depicts cap­tured mem­bers of the German Edel­weiss II weather station on Little Kol­de­wey Island on Octo­ber 4 or Novem­ber 4, 1944 (sources vary), weeks after the capture of Edel­weiss I by the crew of the United States Coast Guard cutter Northland. Edelweiss II was the last of the German weather stations in Greenland.

Right: To show the Allies their willing­ness to fight the Germans in the Arctic deso­la­tion of their home­land, a small band of Danes, Nor­we­gians, and native Green­landers, 15 men in all, came together as the North-East Green­land Sledge Patrol in the sum­mer of 1941. The birth of the patrol was coor­di­nated with the U.S. Coast Guard. The patrol’s acti­vi­ties were to locate and eli­mi­nate German radio and weather stations in Green­land. In March 1943 a dog-team patrol dis­covered the Ger­man weather reporting sta­tion Holz­auge at Hansa Bay on the north­east coast, where it had been oper­a­ting since August 1942. In May 1943 U.S. air­craft from Ice­land bombed the sta­tion, the only offen­sive air attack on the Green­land main­land during the war. The photo in the right frame shows the head­quarters of the Sledge Patrol in the Northern District at Dane­borg/­Sandod­den, Greenland. A flag­pole with the Danish flag sits atop the building.

Newsreel Clip from 1944 Showing the Destruc­tion of a German Radio and Weather Station in Greenland