Bumpass Hell is the largest concentration of hydrothermal features within Lassen Volcanic National Park and offers vivid illustration of the active volcanic processes in the Southern Cascades. Named for an early settler, the area is a popular destination and short hike from the main park road and features fumaroles, hot springs and boiling mudpots.
The hydrothermal features of Lassen Volcanic National Park are due to the boiling of an underground reservoir of hot water, which generates steam that rises to the Earth's surface. The principle discharge area for that steam is Bumpass Hell, and the hottest and most vigorous hydrothermal features in the park can be found there.
The colors of Bumpass Hell are striking and due in part to varying minerals in the waters of the area. The minerals can stain the soils oranges and yellow, and the waters are often bright blue and emerald green.
It is very important to stay on marked trails and boardwalks in Bumpass Hell. The eponymous Kendall Bumpass was a cowboy working in the 1860s who helped discover the area, but lost his leg after his foot broke through the crust he was walking on.
The observable volcanism at Bumpass Hell clearly demonstrates that Lassen Volcanic National Park is still an active region. In fact, the steam escaping the largest fumarole in the park, Big Boiler, has been measured at 322 degrees, making it one of the hottest such features in the world.