The only current visible activity in the Lassen volcanic area is from the various geothermal areas in Lassen Volcanic National Park; boiling hot springs, bubbling mud pots and fuming fumaroles. Most of these features lie in or are closely adjacent to Mount Tehama's caldera. In each thermal area, the highest temperature of water generally is close to the boiling temperature at the altitude of the particular spring or fumarole at Bumpass Hell and on the northwest flanks of Lassen Peak.