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Lassen Volcanic National Park
The southernmost active Cascade volcano and its boiling hydrothermal basins
Lassen Peak awoke in May 1914 and kept erupting for three years. On May 22, 1915, a blast sent an ash column miles into the sky and a mudflow down its northeast flank. Until Mount St. Helens in 1980, these were the most recent eruptions in the Cascade Range. Congress responded by creating Lassen Volcanic National Park in 1916, folding in Lassen Peak and Cinder Cone national monuments established in 1907. At 10,457 feet (3,187 m), Lassen Peak is the largest plug dome volcano in the world and the southernmost active volcano in the Cascade Range.
The park is one of the few places on Earth where all four types of volcano, plug dome, shield, cinder cone and stratovolcano, stand side by side. Boardwalks cross Bumpass Hell, the largest hydrothermal area in the park, where mud pots bubble and fumaroles hiss inside the eroded caldera of ancient Mount Tehama. Heavy snow, often more than 400 inches (10 m) a year at the southwest entrance, closes State Route 89 through the park for much of winter. Atsugewi, Yana, Yahi and Maidu people lived around the mountain, and the visitor center takes its name, Kohm Yah-mah-nee, from the Maidu name for Lassen Peak.