Columbia Icefield

The Columbia Icefield is the largest ice field in North America's Rocky Mountains, straddling the Continental Divide on the Alberta-British Columbia border within Banff and Jasper National Parks. It rests on relatively level rock layers that erode more slowly than the tilted terrain around them, which has helped it hold its high, cold position, and it covers about 325 square kilometers with ice 100 to 365 meters deep, fed by up to 7 meters of snowfall a year. The icefield built up during the Great Glaciation roughly 238,000 to 126,000 years ago, advanced further during the Wisconsinan glaciations, and reached its most recent peak during the Little Ice Age before beginning a continuing retreat after about 1840. It feeds six major glaciers and sits atop a triple continental divide, sending meltwater toward the Arctic Ocean, Hudson Bay and the Pacific Ocean, and gives rise to rivers including the Athabasca and North Saskatchewan.