Lassen Peak

Lassen Peak is a lava dome volcano in Lassen Volcanic National Park in Shasta County, Northern California, standing 10,457 feet high and the southernmost active volcano in the Cascade Range. It is one of the largest lava domes on Earth, with a volume of about 0.6 cubic miles, and formed only 27,000 years ago in a series of eruptions over a few years. On May 22, 1915, Lassen produced a catastrophic explosive eruption that sent ash 280 miles east into Nevada, devastated about three square miles near the volcano and generated lahars that traveled 15 miles from the summit. It has been dormant since 1921 but retains an active magma chamber capable of future eruptions, and its slopes still host fumaroles, hot springs and mudpots.