Alaskan glaciers

Abstract

This entry presents a summary of the distribution, size, behavior, and characteristics of the glaciers of Alaska. It has documented that today, most of Alaska’s approximately 2,000 valley glaciers are retreating, thinning, and/or stagnating. Additionally, many lower elevation mountain and cirque glaciers have disappeared in post-Little Ice Age time. In spite of the regional trend of significant ice loss, about a dozen large valley glaciers are currently thickening and advancing. All of these are near the Pacific Ocean and generally possess significant higher elevation accumulation areas. At higher elevations, generally above 2,000 m, glaciers are thickening or exhibit no change. Several volcanoes, including Redoubt Volcano, had twentieth century eruptions that melted summit glaciers. Post-eruption conditions resulted in the formation of new glaciers in their craters. Recently, space-based investigations have confirmed the role of melting Alaskan glaciers in global sea-level rise and documented the acceleration of the rate of melting and retreat at many locations.