Cascades Volcano Observatory

Because You Care, Be Aware and Prepare

Mount St. Helens and the industrial waterfront area of North Portla...

Mount St. Helens and the industrial waterfront area of North Portland, Oregon along the Willamette River in the foreground. Excess sediment from volcanoes can significantly impact river traffic. (Credit: Ruttledge, Ed. Public domain.)

The May 18, 1980 eruption of Mount St. Helens was the most expensive in US history, costing about $1 billion in damages. The eruption killed 57 people, approximately 7,000 big game animals, and about 12 million fingerlings in hatcheries. Lahars destroyed 27 bridges and nearly 200 homes, and volcanic ash caused the first known in-flight aircraft engine failure plus disrupted thousands of households for many months. Volcanic eruptions in the Cascade Range have occurred at an average rate of 2-3 times per century during recent millennia.

Communities and individuals can minimize loss of life and property by making basic preparations now, such as learning the locations of hazard zones, inquiring about local emergency planning efforts, and preparing households and businesses for emergencies as they would for most other hazards.

There will be some warning before eruption begins, but the time between the first signs and eruptive activity might be short. During the days, weeks, or months prior to volcanism, the movement of rising magma gives detectable signals—heightened gas emissions, deforming of the volcano, and unique earthquake signatures. To keep communities safe, the USGS and its partners at the University of Washington monitor hazardous Cascade volcanoes so that they can detect the onset of volcanic unrest. This is the only way to forewarn communities at risk in enough time to activate emergency response plans, which will ultimately help save lives and property.

We are all in this together. Everyone has a role in preparedness.

Role of the USGS volcano observatories
The US Geological Survey assesses volcano hazards, participates in development of volcano coordination plans, monitors activity of volcanoes, issues warnings of impending eruptions, and delivers eruption updates via Volcano Hazards Program and Volcano Observatory websites, the Volcano Notification Service (VNS) and the media. 

Role of public officials:
Public officials keep their communities safe by developing and exercising emergency plans, and by providing hazards education and notification about local hazards and emergency procedures. During volcanic activity, they can advise residents about closures, evacuation routes, and recommendations for recovery. 

Role of the public
Residents can survive a volcanic eruption with greater safety and less disruption if they learn about the hazards in their communities before an eruption and follow the local recommendations to ensure households and businesses are prepared. Check the volcano hazard maps to identify the potential volcanic processes that put you at risk. See Preparedness Resources for specifics.