Hazards

Several hazards will likely accompany a future eruption of Lassen volcano.

Basaltic lava flows and small, associated, local ash falls, are the most common volcanic activity at Lassen volcanic center.

Volcanic ash travels with the wind, and ashfall can impact areas near to and far from the eruption site.

When pyroclastic flows mix with large quantities of water, they can produce highly mobile flows of mud and debris, called lahars, that may rush down valleys leading away from a volcano.

Explosive eruptions that produce volcanic ash can also form pyroclastic density currents—both pyroclastic flows and surges.

There are landslide and rockfall hazards at Lassen that are not directly related to eruptions.