Start: Bumpass Hell parking area
Bumpass Hell Trail
Rehabilitation efforts are completed on the 1.5-mile trail between Bumpass Hell parking area and Bumpass Hell basin. The resulting trail is wider, smoother, and better designed to withstand erosion.
Hikers will see continuing Bumpass Hell Trail and Boardwalk Rehabilitation Project efforts along the trail and within the basin. This includes restoration of an alternative 0.2-mile basin access trail and overlook enhancement. The second basin trail will remain closed until construction is complete and access to overlooks may be limited.
Seasonal Trail Opening Information
The trail to reach Bumpass Hell is at a high elevation and recieves significant snowpack. Every spring, the trail will close due to severe winter hazards. On average, it opens by Fourth of July weekend each summer, however actual opening dates vary with each year's snow pack. For more information about Bumpass Hell trail status and conditions, please contact the visitor center (530) 595-4480.
Previous trail opening dates: July 13, 2011 | June 29, 2012 | June 25, 2013 | June 11, 2014 | June 7, 2015 | July 9, 2016 | August 22, 2017 | Closed in 2018* | September 13, 2019*
The Largest Hydrothermal Area in the ParkBumpass Hell is the largest hydrothermal area in the park and marks the principal area of upflow of steam and discharge from the Lassen hydrothermal system. The temperature of high-velocity steam jetting from Big Boiler, the largest fumarole in the park, has been measured as high as 322°F (161°C), making it one of the hottest fumaroles in the world. The steam heated waters are typically acidic and are not safe, even for bathing. Learn more about hydrothermal features in Lassen in a U.S. Geological Survey publication, "Hot Water" in Lassen Volcanic National Park.
Last updated: May 14, 2020