National Geographic : 1951 Jun
844 Don C. Knudsen from Frederic Lewis Ice and Water Shooting the Outlet's Rapids Erupt in Spray and Shower a Spectator Glaciers half a mile high stripped this area of soil, talus, and stream gravel during the ice age. Today retreating glaciers. Knik among them, leave amazing changes in the landscape. Lakes appear and disappear; rivers change courses. Debris-veneered valleys emerge where a quarter of a century ago ice may have stood a thousand feet thick. Shrinking glaciers are not confined to Alaska; they seem to be retreating all over the world, suggesting in creasing warmth or decreasing snowfall. Glacier-dammed lakes are rare; drainage seldom is blocked. Greenland, where the ice age remains supreme, contains a few such phenomena. Some of its barricaded lakes stand at different levels on the same ice field. One lake drains through ice to a reservoir 300 feet below. No one knows when Lake George's annual refill began. The late Raymond S. Patton, director of the United States Coast and Geodetic Survey and trustee of the National Geographic Society, made the first written mention in a 1914-15 survey. He quoted one Palmer, an eyewitness in 1910 to the Knik River flood. Mr. Palmer in turn credited a prospector with having stumbled across the outpouring lake while searching for gold. Rock debris, ground by sliding ice until it resembles powdered coal, here covers the opposite bank of the gorge. Jagged walls of bluish-green ice rise above the channel (right). For a week or so the lake level drops about one foot an hour. A huge block of ice, having dropped down the rocky chute, fractures into a thousand fragments, and these, mixed with water, swirl around Mr. Brink as he records sounds.