The eruption of Lassen Peak in 1915 unleashed torrential mudflows—always a threat when hot volcanic material falls on snow-and ice-covered slopes. Triggered by large amounts of melt water, mudflows travel swiftly downslope, inundating valleys and low-lying areas. For most of the snow-capped Cascade Range volcanoes, mudflows pose the greatest danger to nearby communities.

	Dacite		Banded Pumice