Bumpass Hell, Lassen Volcanic National Park, California

Distance: 3 mi (5 km) round trip
Difficulty: Easy
Elevation: 8,000 – 7,700 ft (2,440 – 2,348 m)
Season: July to October

Lassen Peak - one of the largest volcanic domes in the world

If you are at Lassen Volcanic National Park and are looking for a neat little trail to do while visiting the park, then Bumpass Hell is the place to go. There are sulfur vents, mud pots, and boiling hot springs just a little ways from the main cone of the volcano. It's like a mini-Yellowstone.

Lake Helen in early August

Approximately 350,000 years ago, a large stratovolcano called Mount Tehama suffered a catastrophic eruption and formed a large caldera. About 27,000 years ago, a large volcanic plug began to rise up along the edge of this caldera. It eventually formed the 10,000 foot Lassen Peak, which is one of the largest volcanic domes on Earth.

Volcanic bombs from the 1917 eruption along the trail

Lassen Peak last erupted in 1917 and other than Mount Saint Helens, was the last volcano to erupt in the lower 48 states. Bumpass Hell represents an area of heat release on the outer areas of the caldera. This trail is an easy 3 mile (5 km) round trip and is only a 300 foot descent down to the sulfurous basin. These thermal waters are the result of snow and rain percolating through the ground down to the hot magma chamber that remains under the dormant Lassen volcano.

There is a boardwalk in the thermal area for you to explore all of the different pools and mudpots. You should most definitely stay on this boardwalk because the ground is brittle in the area due to the effects of the highly acidic water on the rock and thus you would risk breaking through and sinking your legs into scaulding hot mud.

Just return the way you came. Although, you could extend this hike by going an additional 1.7 miles to Cold Boiling Lake, where bubbles of volcanic gasses rise up from the mud along the edges of the lake.

The boardwalk at Bumpass Hell