The Mount Meager massif 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 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
1980 eruption of Mount St. Helens
1980 eruption of Mount St. Helens
Cascade Volcanoes