<P> On May 22, 1915, an explosive eruption at Lassen Peak devastated nearby areas and rained volcanic ash as far away as 200 miles (320 km) to the east . A huge column of volcanic ash and gas rose more than 30,000 feet (9,100 m) into the air and was visible from as far away as Eureka, California, 150 miles (240 km) to the west . A pyroclastic flow swept down the side of the volcano, devastating a 3 - square - mile (7.8 km) area . This explosion was the most powerful in a 1914--17 series of eruptions at Lassen Peak . </P> <Dl> <Dt> 2350 BP Eruption of Mount Meager </Dt> </Dl> <Dt> 2350 BP Eruption of Mount Meager </Dt> <P> Mount Meager produced the most recent major eruption in Canada, sending ash as far away as Alberta . The eruption was similar to the 1980 eruption of Mount St. Helens, sending an ash column approximately 20 km (12 mi) high into the stratosphere . This activity produced a diverse sequence of volcanic deposits, well exposed in the bluffs along the Lillooet River, which is defined as the Pebble Creek Formation . The eruption was episodic, occurring from a vent on the north - east side of Plinth Peak . An unusual, thick apron of welded vitrophyric breccia may represent the explosive collapse of an early lava dome, depositing ash several meters in thickness near the vent area . </P>

What types of volcanoes are in the pacific northwest