Osceola Mudflow , also known as the Osceola Lahar , was a lahar in the U.S. state of Washington that descended from the summit and northeast slope of Mount Rainier during a period of eruptions about 5,600 years ago . It traveled down the west and main forks of the White River , passed the location of present day Enumclaw then reached Puget Sound near present day Auburn . The Osceola collapse formed a wide horseshoe-shaped crater , open to the northeast , almost the same size as the crater produced by the 1980 eruption of Mount St. Helens . Most of the Osceola crater has been filled in by subsequent lava eruptions , most recently about 2,200 years ago
1980 eruption of Mount St. Helens
1980 eruption of Mount St. Helens
Osceola Mudflow