35th Anniversary of the Eruption of Mount St. Helens

st_helens_bookmark_originalThe months and days leading up to the May 18, 1980 eruption
of Mount St. Helens were tense and filled with a sense of
unknown. Few people really knew that there were giant volcanoes in their backyard, and fewer yet had ever seen such a volcano erupt.

As news and images of the eruption began to circulate, people across the world really began to understand what a volcano can do. The giant ash cloud rose in to the sky, blocking the sun, disrupting flights across the country, and raining shards of volcanic glass and ash across much of Washington and other western states.

As spectacular and terrifying as the eruption was, the damage was just beginning. Giant landslides made from ash and melted snow and ice (called lahars) descended from the mountain and 00151 copyfilled nearby rivers and streams. These lahars carried tremendous amounts of debris, from blown-down trees, to cars and entire houses that destroyed bridges as they flowed downstream.

Summary of volcanic hazards in Washington state

The events of May 18, 1980 helped the residents of Washington and the rest of the nation
know what to expect from future eruptions. Volcanoes line the west coast of the United States, from Mount Baker in northern Washington to Mount Lassen in northern California. Most of these volcanoes have erupted in the past 10,000 years and are considered active, although it is impossible to predict exactly which of the dozen or so volcanoes will erupt next.


Volcanic eruptions are usually, but not always, preceded by changes that can be detected by geologists. Monitoring these ‘vital signs’ is largely the task of the Cascade Volcano Observatory. Visit our website, ready.gov, and the Cascade Volcano Observatory for more information about volcanoes, their hazards, and how to prepare in case of an emergency.

In celebration of the 35th anniversary, we are releasing three sets of annotated slides that document many aspects of the historic eruption. Sets 1 and 2 were previously released, but each photo has been digitally restored in order to remove the ‘smurf blue’ coloring in the original slide or negative. Set 3 has never before been released and contains a series of striking photos recently discovered in our archive.

Slide set #1: 20 slides from March through June, 1980 [PDF; 23MB]

Slide set #2: 20 slides from May 18, 1980 through May 13, 1981 [PDF; 24MB]

Slide set #3: 16 slides from 1974 through 1981 [PDF; 25MB]

Roadside geology of Mount St. Helens National Volcanic Monument and vicinity
Entire guide [PDF; 56MB]
Part 1 [PDF; 28MB]
Part 2 [PDF; 28MB]