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Bumpass Hell, Lassen Volcanic National Park

Geologic Feature
Boardwalks at Bumpass Hell give access to a very active volcanic area. – Ben Miles

ADA Accessibility Notes

The trail to Bumpass Hell is rugged, but some hydrothermal features can be seen from the main park road in places such as the Sulphur Works.

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.

Pet Friendly Notes

Pets must be on a leash while in the park, and are not permitted on the trails.

Recreational Opportunities

The trail to Bumpass Hell measures only one and a half miles. The trail is around 8,000 feet in elevation so the high elevation can make hiking challenging for visitors. It does not feature much elevation change until dropping 100 vertical feet into the basin of Bumpass Hell.

The trail is popular and can be crowded on weekends and holidays. It is often open while there are still significant amounts of snow still present on the trail, which can make for a challenging descent down steeper portions. Hiking boots are a must even into the summer, as a lingering snow field can still be found in July and August.


Seasons Accessible

The main park road (Highway 89) is closed more than half the year. Park workers are usually able to clear it by the first of July, but the trail to Bumpass Hell may not open until a few weeks after that. Even when the trailhead is accessible, be prepared to encounter large amounts of snow early in the season.


Park entrance to Lassen is $10 for seven days.

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