About 5 percent (about 75,000 km2) of Alaska is presently glacierized, including 11 mountain ranges, 1 large island, an island chain, and 1 archipelago. The total number of glaciers in Alaska is estimated at >100 ,000, including many active and former tidewater glaciers. Glaciers in every mountain range and island group are experiencing significant retreat, thinning, and (or) stagnation, especially those at lower elevations, a process that began by the middle of the 19th century. In southeastern Alaska and western Canada, 205 glaciers have a history of surging; in the same region, at least 53 present and 7 former large ice-dammed lakes have produced jökulhlaups (glacier-outburst floods). Ice-capped Alaska volcanoes also have the potential for jökulhlaups caused by subglacier volcanic and geothermal activity. Satellite remote sensing provides the only practical means of monitoring regional changes in glaciers in response to short-and long-term changes in the maritime and continental climates of Alaska. Geospatial analysis is used to define selected glaciological parameters in the eastern part of the Alaska Range.