In 1864 a mountain man named Kendall Vanhook Bumpass was exploring the geothermal areas on the side of Mount Lassen in Northern California. Not understanding the nature of this area of mudpots, boiling pools and fumeroles, Bumpass was less careful than he should have been and fell through the thin crust covering one of the pools. One leg was badly burned and eventually had to be amputated. The area was christened Bumpass Hell in his honor, and several other geographic features have adopted the name as well (Bumpass Creek, Bumpass Meadows and Bumpass Mountain). And just so you know....it's not really pronounced bump-ASS, the correct pronunciation is BUMP-uss..just like the infamous Bumpass Hounds in the movie Christmas Story.
Bumpass Hell is sixteen acres of unearthly colored boiling pools, hissing, steaming holes and bubbling mudpots. The air is full of steam and sulfur. The surrounding area consists of unusual multi-hued soils, stained orange, brown, yellow and green by sulphur and other minerals. All this weirdness happens because this is part of the region once covered by the ancient volcano Mount Tehama and is still very active volcanically. A huge mass of underground magma heats ground water to steam, which presses to the surface to create burping mudpots, hissing fumaroles, and bubbling pools which bathe you in odoriferous hot vapor. It is probably of no immediate concern, but some of the hot pools at Bumpass Hell are becoming gradually hotter, a sign of increased geothermal activity in the region and a possible precursor of future volcanic eruptions. Mount Lassen, the active volcano on which Bumpass Hell is located last erupted on on the night of 19 May 1915.
Bumpass Hell may be reached today from a well-marked 1.5 mile trail that crosses generally rocky land with some tree cover, and without much change in elevation. Once you reach the area, a network of wooden walkways allows closer, safer looks at the pools, mudpots and steam vents. Warning signs instruct hikers to stay on the boardwalks so as not to share the fate of Kendall Bumpass, and inform readers that 21 people in the past 10 years have been seriously burned by straying off the walkways. It's a pretty amazing thing to see. Bumpass Hell, and Lassen National Park in general, has 3 of the 4 main types of geothermal features (fumaroles, mudpots and hot springs); the only phenomena missing are geysers, since these require rather specific conditions of rock type, sub-soil temperature and water depth.
Bumpass Hell is located at a very high elevation (over 8000 feet), which means that the area is inaccessible much of the year due to snow. The parking lot to the trail is used by star-gazers for frequent star parties due to the clear air, mostly unobstructed view of the night sky, and lack of background lights in the area.