What is a Volcano?
A volcano is an opening in Earth’s crust through which magma, rocks, ash, and gases erupt from beneath the ground. Over many eruptions, these materials pile up and form a volcanic mountain.
Washington’s Volcanoes & Risks
Washington has five major volcanoes in the Cascade Range:
Mount Baker
Glacier Peak
Mount Rainier
Mount St. Helens
Mount Adams
These volcanoes can be dormant for centuries, but that doesn’t mean they’re harmless. When they erupt, several hazards occur:
Pyroclastic flows (fast, extremely hot avalanches of ash and rock)
Lava flows and fast landslides
Lahars—mudflows or debris flows that follow river valleys, often traveling far downstream
Ashfall—fine ash carried by wind can affect areas far from the volcano, disrupting daily life, air travel, machinery, and health.
Because many people live near or downstream of these volcanoes, the risk is significant even for eruptions that are not massive.
Monitoring & Alert Levels
Volcanoes in Washington are closely watched by USGS’ Cascades Volcano Observatory. They track various signs of possible unrest, such as:
Changes in the number of earthquakes
Gas emissions
Deformation of the volcano (rising or sinking of the ground)
All five volcanoes are currently classified at a “Normal” or background alert level, meaning there is no immediate danger.
Threat Levels & Specific Volcanoes
Mount St. Helens and Mount Rainier are among the most dangerous volcanoes in the U.S., based on how many people live nearby, how explosive past eruptions have been, and how much ash they produce.
Mount Baker and Glacier Peak are also rated as “very high” threats. Mount Adams is currently considered a “high” threat, though not as explosive historically.
Preparedness & What You Can Do
Washington State has coordination plans involving multiple agencies (local, tribal, state, federal) to prepare for volcanic emergencies. These define who does what in case of an eruption.
Residents are encouraged to be ready for disasters in general, including volcano-related ones. This means planning for possible ashfall, lahars, and other secondary hazards.
Public awareness and drills (for example, lahar drills in schools) are part of preparation efforts so people know what to do if things escalate.
