Bumpass Hell and Bumpass Mountain of Lassen Volcanic National Park

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3D map with Bumpass Hell, Lake Helen and Lassen Peak Boiling pool
3D map with Lassen Peak and Bumpass Hell Trail
3D map with Lassen Peak and Bumpass Hell Trail
Boiling pools steaming near the boardwalk
Boiling pools steaming near the boardwalk

Bumpass Hell, named after ill-fated K. V. Bumpass (1809-1885), is a boardwalk-accessible 16-acre hydrothermal area in Lassen Volcanic National Park, California. A Lassen Volcanic terrain model in the Loomis Museum features the park's natural sites and their road and trail connections. The left-side picture above shows a section of this raised-relief map tracing Lassen Peak Trail and the popular Bumpass Hell Trail, which begins next to Lake Helen and leads over a saddle into the colorful and smelling world of hot springs, mudpots and fumaroles.

The right pictures shows pools of boiling water belonging to the over 75 hydrothermal features there, through which heated groundwater and gases are escaping into the atmosphere. The groundwater deep below the fractured surface (over which you are guided when visiting Bumpass Hell) is heated by chambered magma that fed the eruptions of Lassen Peak and its nearby volcanic companions. One furnace, one system is what an on-site interpretive panel is pointing out. And another panel explains: Bumpass Hell occupies the old eroded vent of a dormant dome volcano— Bumpass Mountain.