Mount St. Helens, WA simplified hazards map showing potential impac...

Mauve indicates areas at risk from lava flows and avalanches of hot rock and gases called pyroclastic flows. Bright red areas that fade to orange and yellow indicate potential routes for lahars (volcanic mudflows). Not shown are areas subject to hazards from volcanic ash. Volcanic ashfall is often a nuisance but can be a more serious hazard during large explosive eruptions.