‘The Great Eruption’ of Lassen Peak, CA in 1915 is second only to the eruption of Mt. St. Helens in 1980 as the most powerful volcanic eruption of the last century. This eruption occurred on May 22, 1915, was part of a series of eruptions that took place between 1914 and 1917, and rocked the state and devastated surrounding regions.
Lassen Peak, commonly referred to as Mount Lassen, is the southernmost active volcano in the Cascade Range of the Western United States. Located in the Shasta Cascade region of Northern California, it is part of the Cascade Volcanic Arc, which stretches from southwestern British Columbia to northern California. The Peak reaches an elevation of 10,457 feet (3,187 m), standing above the northern Sacramento Valley – Wikipedia
Snow mixed with volcanic materials created massive mudflows, hot gas and rock destroyed Lassen’s immediate surroundings, and volcanic ash rained down on landscapes as far as 200 miles away. The eruption column was seen as far away as 150-miles.
A whole side of the peak was lost during one of the eruptions. When you look at Lassen Peak today, you’re looking at a different peak than existed before those eruptions occurred.
Although Lassen Peak is now regularly monitored, it’s hard to determine when the next eruption will take place. It could be hundreds or thousands of years from now.