The 6-mile (10-kilometer) long Quake Lake began to fill in 1959 when an earthquake-triggered landslide plugged the Madison River canyon. The slide buried 19 campers, but protected the lower Madison Valley from the tsunamis that sloshed over Hebgen Dam higher up the canyon.
The earthquake was measured at a magnitude 7.3 - 7.5 on the Richter scale, and was one of the strongest and deadliest to occur in Montana in the last 100 years. The landslide was one of the most-costly ever in the Northwest United States.
A visit to the Visitor's Center provides informative exhibits of the damage caused by the earthquake and ensuing landslide, as well as scenic overlooks, films, and much more.