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Earthquake Lake

On August 17t 1959 at 11:37 PM several fault in the Madison River Area moved at the same time causing an earth quake that triggered a massive landslide. The slide moved at 100 miles per hour and happened in less than one minute. Over 80 million tons of rock crashed into the narrow canyon, burying an open meadow where some campers had stopped for the night. The Landslide had completely blocked Madison River and caused it to from Earthquake Lake. The force of the slide displaced both the air in the canyon and the water of Madison River. It created high velocity winds and a wall of water that swept through the area, just downstream from the slide, killing five people in its path. Earth Quake Lake

The Hebgen Lake earthquake measured 7.5 on the Richter scale. At least three block of the Earth’s crust suddenly dropped as two faults moved simultaneously…the Red Canyon Fault and the Hebgen Lake Fault. The north shore of Hebgen Lake dropped 19 feet and cabins fell into the water. Hebgen Lake sloshed back and forth. Huge waves called seiches crested over Hebgen Dam. This earth-filled dam cracked in four places, but held. Three sections of Highway 287 fell into the lake. Hundreds of campers were trapped. 28 people lost their lives as a result of the earthquake. Their names appear on a bronze plaque on one of the massive dolomite boulders carried across the canyon by the slide. The dolomite boulder serves a as a memorial.