Park Highway Closed for Winter Season
Lassen National Park Highway is closed to through traffic for the winter season. The highway will remain open to the the Kohm Yah-mah-nee Visitor Center (1 mile from the SW entrance) and Manzanita Lake (1 mile inside the NW entrance). More »
Volcanoes / Lava Flows
(B. F. Loomis)
Every rock at Lassen originates from volcanoes. Lassen's volcanic domes are part of the most recently active Lassen Volcanic Center, which began to erupt about 825,000 years ago. Represented in the park are all four types of volcanoes found in the world--shield, composite, cinder cone, and plug dome. Unlike other Cascade volcanoes, Lassen's large plug dome and composite volcanoes are in close proximity to the smaller cinder cone volcanoes that surround the volcanic center.
The greater Lassen area has been volcanically active for about three millions years. Recently the region has seen eruptions from Cinder Cone (~350 years ago) and Lassen Peak (~100 years ago). While the area sleeps now, steam vents, boiling springs, and bubbling mudpots remain active--direct evidence that the volcanic center still smolders. No one can say when or where the next eruption will occur. We can only say that it will.
New! Recent Volcanic Activity
The volcanoes of Lassen The volcanoes in Lassen Volcanic National Park are monitored by the United States Geological Survey (USGS). Seismic stations located throughout the park allow scientists to measure earthquakes in real-time. A new exhibit in the Loomis Museum includes an interactive map displaying sesimic stations and recent earthquakes within the park. This same map is visible online as part of the California Volcano Observatory.
USGS measures seismic stations in active areas worldwide with the goal of predicting hazardous conditions. Worldwide earthquake activity, including the recent Lake Almanor earthquakes, can be viewed on the USGS website.
Studying and Monitoring Volcanic Activity
Lassen Volcanic Interactive Monitoring Map
Eruption Probabilities for the Lassen Volcanic Center
Did You Know?
The 29 mile Main Park Road was constructed between 1925 and 1931, just 10 years after Lassen Peak erupted. Near Lassen Peak the road reaches 8512 feet, making it the highest road in the Cascade Mountains. It is not unusual for 40 feet of snow to accumulate on the road near Lake Helen.