Bumpass Hell
Bumpass Hell reaches a boiling 199°F at Lassen Volcanic National Park's 8,017-foot summit zone, creating the park's largest and most spectacular hydrothermal field. This permanent natural-state preserve with open public access showcases the dramatic intersection of volcanic activity and high-altitude alpine terrain.
A short walk of approximately 4,200 feet from Lassen Peak Highway ascending through subalpine forest reaches this explosive geothermal landscape. Upon arrival, the terrain transforms dramatically—colorful mineral deposits paint the ground in yellows, oranges, and whites while steam vents and boiling mud pots testify to ongoing subsurface activity. The setting combines raw geological power with the fragile beauty of high-alpine vegetation struggling to survive in harsh conditions.
Named for a 19th-century hiking guide reputedly burned by the scalding water, Bumpass Hell represents one of North America's most accessible major geothermal fields. The area's boiling pools, mud pots, and steam vents directly reflect the underlying magmatic system that fuels Lassen Peak itself. Geological monitoring documents ongoing changes in temperature and mineral chemistry as subsurface conditions evolve.
The moderately strenuous 4,200-foot hike rewards visitors with views unavailable from any road. Arrive early to secure parking and avoid crowds. Conditions vary dramatically by season—late June through September offer snow-free hiking, while spring and fall present variable conditions. Stay strictly on marked trails; thermal features concentrate in small areas surrounded by boiling water and unstable ground.
Is Bumpass Hell worth visiting?
Best for
- Observing powerful hot springs
- Overnight camping trips
- Winter soaking with dramatic temperature contrast
Not ideal for
- Casual soaking
The water at Bumpass Hell is neutral (pH 6.9) with 42 mg/L total dissolved solids.
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Overview Summit Lake South Campground (elevation 6,700 ft.) is conveniently located on the main road of Lassen Volcanic National Park. The campground is within walking distance of the small but scenic Summit Lake and eight miles from the 10,457-ft. Lassen Peak, the largest volcano in the park. Hikers will find one of the park's major trails only 1/4-mile away from the campground and many more within a close proximity. Summit Lake South is on the opposite side of the lake from Summit Lake Nort...