Wrangell-St. Elias National Park and Preserve contains several of North America's highest peaks, including Mt. St. Elias (18,008 feet) and Wrangell Mountain (14,005 feet), an active volcano. From these mountains flow hundreds of glaciers varying tremendously in size. The Malaspina is one of the largest piedmont lobe glaciers and the Nabesna Glacier is one of the longest valley glaciers (over 40 miles long). Other glaciers terminate at tidewater and are known for their surging and retreating. Extensive ice fields also occur within the mountain ranges.