Fumarole and on the surfaces of lava flows and of thick deposits of pyroclastic flows. A fumarole field is an area of thermal springs and gas vents where magma or hot igneous rocks at shallow depth release gases or interact with groundwater. When they occur in freezing environments, fumaroles may cause fumarolic ice towers. Fumaroles may persist for decades or centuries if located above a persistent heat source; or they may disappear within weeks to months if they occur atop a fresh volcanic deposit that quickly cools. The Valley of Ten Thousand Smokes, for example, was formed during the 1912 eruption
West Crater imply that they resulted from the same movement of magma and were possibly fed by the same magma chambers. The lava dome likely formed before the lava flows erupted, suggested by its steep western side and the appearance of rock from the dome on the western lava flow. The dome's deep depression may have formed when the dome's top collapsed as lava moved out of the volcano during the eruption of the two flows. The human population within of West Crater is slightly more than 500 people, but more than 14,000 people live within of the volcano, and more than