<Tr> <Th> Easiest route </Th> <Td> Hike </Td> </Tr> <P> 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, Lassen stands 3,500 ft (1,100 m) above the surrounding terrain and has a volume of 0.5 cu mi (2 km), making it one of the largest lava domes on Earth . It arose on the destroyed northeastern flank of now - gone Mount Tehama, a stratovolcano at least 1,000 ft (300 m) higher than Lassen Peak . It is part of the Cascade Volcanic Arc, which stretches from southwestern British Columbia to northern California . </P> <P> On May 22, 1915, a powerful explosive eruption at Lassen Peak devastated nearby areas, and spread volcanic ash as far as 200 mi (300 km) to the east . This explosion was the most powerful in a series of eruptions from 1914 through 1917 . Lassen Peak and Mount St. Helens were the only two volcanoes in the contiguous United States to erupt during the 20th century . Lassen Volcanic National Park was created in Tehama County, California, to preserve the devastated areas as they were, for future observation and study, and to preserve the nearby volcanic features . </P> <P> Lassen Peak has the highest known winter snowfall amounts in California . There is an average annual snowfall of 660 in (1,676 cm), and in some years, more than 1,000 in (2,500 cm) of snow falls at its base altitude of 8,250 ft (2,515 m) at Lake Helen . The Lassen Peak area receives more precipitation (rain, sleet, hail, snow, etc .) than anywhere in the Cascade Range south of the Three Sisters volcanoes in Oregon . The heavy annual snowfall on Lassen Peak creates fourteen permanent patches of snow on and around the mountain top, despite Lassen's rather modest elevation, but no glaciers . Lightning has been known to strike the summit of the volcano frequently during summer thunderstorms . </P>

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