Copyright Information: All images are in the public domain and available for free. If you use this image, credit NOAA/NGDC, Edwin Harp, U.S. Geological Survey. |
On July 11, 1996, at 7:00 P.M. Pacific Daylight Time, a huge rock weighing 200 tons broke away from Glacier Point, near Happy Isles, a popular trailhead and concession stand. The rock disintegrated when it landed, creating an air blast that was so powerful that it flattened as many as 2,000 trees in the area. The rockfall deposition killed one person at a concession stand, and seriously injured 14 others. The dust kicked up from the pulverized granite blocked out sunlight and coated tents and recreational vehicles, similar to ashfall from a volcano. Massive rockfalls continue to occur. In 1999, a rockfall in the same area killed one climber and injured several others. Image Credit: Edwin Harp. U.S. Geological Survey The slopes above streams and rivers are subjected to a variety of processes that cause them to recede and retreat from the river or stream channel. These processes, collectively called mass wasting, can be classified according to rapidity of movement and according to the type of materials that are transported. |
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