On Aug. 17, 1959 the earth around Yellowstone shook. At 11:37 p.m. a 7.3 magnitude earthquake devastated Hebgen Lake, Mont., located in Yellowstone’s northwestern region—in comparison, the 2010 earthquake in Haiti registered at a 7.0 magnitude. The quake caused massive damage, including 28 fatalities and a considerable $11 million in repairs to highways and timbers. Comparably, recent small quakes in Yellowstone (also called an “earthquake swarm”) registered at 0.6 to 3.6 on the Richter scale.
Joann Smith, who was 11 years old at the time of the disaster, recalled the horror of the event for a 50th anniversary article for the Denver Post published Aug. 17, 2009.
“It was frightening. It was horrible,” she said. “You could actually see the ground open up.”
Smith’s recollections aren’t exaggerated. The United States Geological Survey calls the earthquake the worst on record in Montana (records date back to 1869). The event caused a massive avalanche of rock, soil and trees (an estimated 28-33 million cubic meters of material), which descended down from the Madison River Canyon’s south wall.
“The shaking and the noise was horrific,” John Owen, then 15, told the Post. “It was just way louder than thunder — just one of the loudest noises I’ve ever heard in my life.”
The fallen material formed a wall blocking the Madison River’s flow. After only three weeks the damned river created a lake more than 170 feet deep.
Overall, massive devastation wreaked havoc on much of the area. The summer houses stationed along Hebgen Lake sustained shifted foundations, crumbled chimneys and burst pipelines. Roads cracked and shifted, and three of the five reinforced bridges located near the quake’s center were severely damaged, and large portions of nearby forests were destroyed.
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