Ice Avalanche (Glacier)
Another phenomenon similar to the avalanche is the glacier, or ice avalanche. Glaciers are huge slabs of ice that form in cold regions, usually on slopes. They move very slowly downward. Because their movement is so predictable, they seldom cause much injury or damage. Surprisingly, however, one of the worst avalanche disasters in history was caused by a glacier in Santa Valley, Peru.
At 6:13 p.m. on January 10, 1962, a telephone operator in a town far away from Santa Valley saw a huge white cloud rise over four-mile-high Devado de Huascarán, the second highest mountain in the South American Andes. A one-half mile long chunk of ice had separated from the peak’s 180-foot-thick icecap. The four million tons of ice that fell down the mountain was four times the size of New York’s Empire State Building. Tearing dirt, rock, and boulders from the slopes, it traveled 11 miles in 15 minutes. Seven villages were buried beneath the snow. Scientists can only guess that close to 4,000 lives were lost, buried beneath debris that stretched one mile wide and 45 feet deep.
In 1970, the same thing happened again to Santa Valley. Again, a combination of ice, rock, and mud fell down the slopes. However, this time an earthquake shook loose the icecap on a northern peak. The mountain itself collapsed. The thousands of tons of snow, rock, and ice moved 200 miles per hour through a narrow gorge, surging through the valley and scooping up boulders and houses along the way. When it reached the river, the torrent became a mudflow. It is estimated that 25,000 people died.