Retreating Northern Hemisphere Snow Cover
May 16, 2001
By mid May, the Northern Hemisphere snow cover has usually retreated into north-central Canada. That's the case, this year as well. The average snow cover extent for the Northern Hemisphere, in mid May, is approximately 20 million square kilometers. The snow line is south of the Arctic Circle (66 1/2 degrees north latitude) but is north of much of the boreal forest zone in central and eastern Canada and in western Europe. Notice that Lake Winnipeg (50 degrees north) is still frozen and that sea ice is still found along the Nefwoundland/Labrador coast. With 24 hours of daylight present now, north of 70 degrees north latitude, the snow line will rapidly retreat toward the Arctic Ocean in the coming weeks.