Located in Lassen Volcanic National Park, Bumpass Hell is 16 acres of boiling springs, mud pots, hissing steam vents and roaring fumaroles. Now that’s my kind of hell.
Bumpass Hell is named after Kendall Vanhook Bumpass who stumbled on this area in the late 1800’s while hiking.
It is named Bumpass Hell because he actually fell in one of the steam geysers and ended up losing a leg.
The parking lot near the trailhead is located next to Lake Helen which overlooks Lassen Peak.
The 1.5 mile path from the Lake Helen trailhead is quite easy, crossing generally rocky land partially covered by trees, and without experiencing much change in elevation.
It curves round a ridge extending west from Bumpass Mountain, and ends with a 200 foot descent into the basin.
If you jump you’re going to hell…Bumpass Hell that is.
Brokeoff Mountain (no relation to Brokeback).
Mt. Tehama, or the Brokeoff Volcano, began erupting around 600,000 years ago just south of the present-day site of Lassen Peak. It was a stratovolcano similar to Mt. Shasta or Mt. Hood, composed mainly of gray andesite with interbedded ash and lava flows. The mountain alternated between explosive eruptions and effusive eruptions and eventually grew to a height in excess of 11,000 feet, hundreds of feet higher than modern Lassen Peak (10,457 feet). From the Bumpass Hell trail, the peaks of Brokeoff Mountain and Mt. Diller seem to provide a near-perfect profile of the long-gone volcano, but the original edifice was much larger, something like 15 miles around. The center of the volcano was in the foreground and the two peaks were just part of the western flank.
The active area can be seen (and smelt!) from far away – a wide basin filled with various steaming pools and unusual multi-colored soils, stained orange, brown, yellow and green by sulphur and other minerals.
You get a good overall view of Bumpass Hell from several elevated vantage points…
…before the trails descend, and connect with several raised wooden walkways that traverse the unstable ground and lead towards particular points of interest.
Most noticeable are several large hot pools, gray-blue in color and up to 50 feet across, often with simmering, bubbling water in places. There are also many mudpots of varying viscosity; some are quite thin and effervesce vigorously whereas the less active ones have the consistency of treacle and plop every few seconds.
Other features include small water fountains, steaming soil, noisy fumaroles (sulphurous steam vents) and run-off channels with warmish acidic water, edged by colorful mineral deposits.
Three of the pools have an official name: East Pyrite Pool is perhaps the most unusual, a large, sunken hot spring filled with seething acidic water topped by layers of molten grey/black iron pyrite. On the opposite side of the boardwalk, West Pyrite Pool is a calmer but prettier spring containing turquoise water, surrounded by mostly white rocks colored yellow and brown by iron and sulfur.
The temperature of high-velocity steam jetting from Big Boiler, the largest fumarole in the park, has been measured as high as 322°F, making it one of the hottest fumaroles in the world.
All the springs within the basin produce enough water to form a small stream (Bumpass Creek), which after exiting the basin flows steeply southwards through a narrow, inaccessible ravine lined with other thermal vents.
Yes it’s that green.
Bumpass Hell, and Lassen Volcanic National Park in general, has three of the four main types of geothermal feature (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.
A U.S. Geological Survey Fact Sheet explains that water from rain and snow falling on highlands of the park enters the ground through permeable rock and pathways such as fractures, faults and volcanic flow boundaries. Deep underground it is heated by a body of magma or solid but very hot rock and then raises from 5–6 miles below the surface to about one mile to half a mile below where it accumulates at temperatures of 455–464°F. As it rises acids react with surrounding rock enriching in dissolved silica and metals. As the superheated water gets closer to the surface lower hydrostatic pressure causes it to boil eventually reaching the surface through fissures as steaming fumaroles or boiling at the water table creating areas of steaming surface features such as boiling mudpots and pools.
A process called hydrothermal alteration which happens when acidic water chemically changes minerals in rocks produces a white material rich in kaolinite clay and silica which is abundant at Bumpass Hell.
Bumpass Hell contains around 75 active features but many are either small or not properly visible from the path.
Hold on to your kids or they may just end up as Bumpass Hell’s Soup of the Day.