The Athabasca is the most-visited glacier on the North American continent. Situated across from the Icefield Centre, its ice is in continuous motion, creeping forward at the rate of several centimeters per day. Spilling from the Columbia Icefield over three giant bedrock steps, the glacier flows down the valley like a frozen, slow-moving river. Because of a warming climate, the Athabasca Glacier has been receding or melting for the last 125 years. The Columbia Icefield is a surviving remnant of the thick ice mass that once mantled most of Western Canada's mountains. Lying on a wide, elevated plateau, it is the largest icefield in the Canadian Rockies. Nearly three-quarters of the park's highest peaks are located close to the icefield.