Madison River Canyon Earthquake
One of the largest earthquakes in US history
Overview
The Madison River Canyon Earthquake shook the Gallatin National Forest and Yellowstone National Park in 1959.
Upstream, the quake created gigantic waves in Hebgen Lake that swayed from one shore to the other. Huge swells of water rushed downstream with nowhere to go, flooding cabins, destroying homes and sweeping away survivors. In all 28 people died, either buried beneath the rubble of the slide or drowned by the waves of water from the lake. It was an earth shaking event that left its mark not only on the families of those who lost loved ones, but also on the landscape of the Gallatin National Forest and southwestern Montana.
Quotes from Local Newspapers
– Montana Standard; 1959
– Bozeman Daily Chronicle; 1959
– Bozeman Daily Chronicle; 1959
– Salt Lake Tribune; 1959

The Quake
For more than 11 hours after the quake, the lake rolled from one shore to the other.
Two of these blocks tipped up causing Hebgen Lake to roll 19-feet northward, resulting in a giant wave known to geologists as a “seiche” (pronounced saysh). For more than 11 hours after the quake, the lake rolled from one shore to the other damaging Hebgen Dam and sending four large surges of water pouring over it. The quake’s epicenter, a point on the surface directly above where an earthquake originated, was located at a depth of 11 kilometers beneath Hebgen Lake. It produced large scarps along the fault lines and instantly created cliffs where none once stood, some as high as 20-feet. The two largest, the Red Canyon and Hebgen Fault scarps, extend more than 14-miles each. These scarps can still be viewed today. The best example can be found at Cabin Creek near the Hebgen Dam. Smaller scarps shot across highways and split roads throughout the area. Several large sections of Highway 287 dropped into Hebgen Lake, making escape perilous for survivors and delaying rescue efforts.

Survivors said it looked like the whole mountain had fallen on them.
Buried beneath the rockslide at the bottom were vacationing campers and tourists at a Forest Service campground. Some survivors were trapped while others drowned from surging waters. In all there were 28 victims of the quake, 19 are most likely still buried beneath the slide. Soon after the event, Forest Service smokejumpers parachuted into the area to set up communications and give immediate assistance. The Montana Civil Defense Director, Hugh Potter, mobilized state and federal agencies as rescue efforts continued for several days. The injured were flown out by Air Force and Forest Service helicopters. The Madison River Canyon Earthquake was felt in an eight-state area and surface damage extended from the Old Faithful Geyser in Yellowstone National Park, west nearly 50 miles. Effects from the quake were even observed in water wells as far away as Puerto Rico.
Survivors said it looked like the whole mountain had fallen on them.
Buried beneath the rockslide at the bottom were vacationing campers and tourists at a Forest Service campground. Some survivors were trapped while others drowned from surging waters. In all there were 28 victims of the quake, 19 are most likely still buried beneath the slide. Soon after the event, Forest Service smokejumpers parachuted into the area to set up communications and give immediate assistance. The Montana Civil Defense Director, Hugh Potter, mobilized state and federal agencies as rescue efforts continued for several days. The injured were flown out by Air Force and Forest Service helicopters. The Madison River Canyon Earthquake was felt in an eight-state area and surface damage extended from the Old Faithful Geyser in Yellowstone National Park, west nearly 50 miles. Effects from the quake were even observed in water wells as far away as Puerto Rico.
The Aftermath
To keep the slide material from floating downstream, the Corps of Engineers lined the spillway with large dolomite boulders off the mountain. But when completed the spillway almost immediately began to erode. So the Army Corps of Engineers cut a new spillway at a lesser grade along its center, leaving some sections 50-feet deep. This new spillway dropped the lake level 50-feet and set Earthquake Lake’s level at about 190-feet at its deepest.


What is a seiche?
A seiche (pronounced saysh) is a giant wave produced by an earthquake. The Madison River Canyon Earthquake produced a seiche when Hebgen Lake tipped and water began to slosh from one lake shore to the other. Waves 20-feet high surged over Hebgen Dam and rushed downstream. These waves continued for more than 11 hours, taking 17 minutes to wash from one shore to the other. When the waves finally subsided, cabins on one side of the lake stood underwater. On the opposite side muddy parcels of the lake bottom lay exposed. These waves of water along with the outflow of the Hebgen Lake formed Earthquake Lake.
What is a fault scarp?
A fault scarp is a fresh cliff-like break in the ground caused by an earthquake. The Madison River Canyon Earthquake was a relatively shallow quake meaning it formed a significant number of scarps and cliffs between 9 and 20-feet high. The largest two, the Red Canyon and the Hebgen Fault scarps, extend for more than 14 miles each. New waterfalls formed where scarps crossed streams. Others shot across roads and highways ripping the earth’s surface, leaving in their wake downed trees and houses.
Survivor Stories
A family staying at a motel on Highway 287 was so frightened by the earthquake that they piled into their car in their pajamas and attempted to flee. Unaware that several large sections of the highway were ripped up by the quake, they drove their car full-speed directly off a 6-foot scarp. The vehicle plummeted off the cliff and rolled over on the ground below. Amazingly the family survived with only minor injuries. Crawling from the wreckage, they walked back to the motel they’d just left. Others attempting to flee were forced to return as well. Roads were impassable due to large crevices and scarps. Most were trapped in the area for several days and some spent their time aiding the wounded. Other survivors were hysterical. One man refused help stating he wouldn’t leave, “until he could find his teeth.”
Read publications on the event
Forest Service publication
Madison River Earthquake Disaster Report
August 1959
The Montana Traveler
Madison River Canyon Earthquake Article, 2003
The Night the Earth Shook excerpt
Forest Service publication, 1962
Jumper Recounts Yellowstone Quake Rescue
Bob Nicol, 2014
Visit the Earthquake Lake Visitor Center
The center provides a panoramic view of the area and hosts exhibits on earthquakes and plate tectonics. There is a working seismograph and movies are shown about the 1959 event in the observatory. Outside, a walking path with interpretive signs leads to the Memorial Boulder, which was dedicated to those who lost their lives in the landslide.
The Earthquake Lake Visitor Center is open daily from May through September from 10 am to 6 pm. For more information call 406-682-7620.
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