The Osceola Mudflow, also known as the Osceola Lahar, was a debris flow and lahar in the U.S. state of Washington that descended from the summit and northeast slope of Mount Rainier, a volcano in the Cascade Range 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 in several areas, including near the present day sites of Tacoma and Auburn.
Mount Rainier with its main summit, Columbia Crest (14410 feet) at the center. Emmons Glacier covers most of the visible flank of the mountain with Disappointment Cleaver visible below Gibraltar Rock, right of the sharp pointed Little Tahoma (11138 feet). Liberty Cap (14112 feet) is visible on the right center skyline behind Russell Cliff.
A lahar is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley.
A lahar travels down a river valley in Guatemala near the Santa Maria volcano, 1989
Excavated 9th century Sambisari Hindu temple near Yogyakarta in Java, Indonesia. The temple was buried 6.5 metres under the lahar volcanic debris accumulated from centuries of Mount Merapi eruptions.
Mudline left behind on trees on the banks of the Muddy River after the 1980 eruption of Mount St. Helens showing the height of the lahar
The aftermath of a lahar from the 1982 eruption of Galunggung, Indonesia
