Time lapse cartoon of a massive summit landslide that triggered a l...

A mass of sliding rocks, snow, and ice swept down the northeast side of Mount Rainier about 5,600 years ago, removing a large portion of the summit of the volcano and creating a deep horseshoe-shaped crater. This volcanic landslide was accompanied by a small explosion, and it transformed into an enormous lahar known as the Osceola Mudflow that swept into Puget Sound more than 50 km downstream.