Word: catchment
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Dates: during 1930-1939
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...Recent rains would not cause the glacier to move. Earthquakes or a couple of winters of unusually heavy snows ten years ago, or both, are the cause. The whole area of Alaska is an earthquake zone. Added weight in the ice-filled catchment basin, caused by new snows or an earthquake avalanching down old ice and snows from the higher slopes forces an impulse through the glacier. It is a wave motion and the longer the glacier, the longer it takes to reach the foot. Scientists pooh-poohed a man named Lawrence Martin when he declared right after the Alaskan...
...Zealand and Greenland, only move 30 feet per day." Dismissing the report from Scientist Geist that heavy rains have possibly released soft material along the contact points and lubricated the glacier's groove, causing it to move. Glacialist Washburn explained that glaciers move because of pressure in their catchment basins at their sources. Alaska's glaciers are survivals of the ice age on the North American continent. Washburn believes that Alaska's glaciers are dwindling, will eventually disappear. The Black Rapids Glacier is a case in point...
...this movement exhausts the catchment basins. And even the heaviest Alaskan snowfalls we can hope to expect, are inadequate to compensate. This wave motion has a suction effect, drags a lot of ice with it, thins the glacier over its length. When the impulse has expended itself, there follows a period of very rapid shrinkage at the foot of the glacier. Black Rapids Glacier may continue to move for six months to two years. Then it will recede. Five years hence it will have dwindled five miles back up its valley...