Mount St. Helens National Volcanic Monument is a United States National Monument that is located in southwest Washington State was the site of a massive volcanic eruption on May 18, 1980. It can be visited as a longish day trip from Seattle or Portland, or more conveniently as a side-trip while traveling between the two cities.

History

On March 20, 1980, Mount St. Helens awakened from over 100 years of dormancy with a magnitude 4.1 earthquake which began a series of events leading to eruption. Steam and ash eruption started on March 27, and over the next two months the north side of the mountain started bulging at the rate of about 5 to 6 feet a day.

Then on May 18, 1980, at 8:32 a.m., a magnitude 5.1 earthquake caused the bulging north face to collapse in one of the largest landslides in recorded history. The highly pressurized magma burst forth in an explosive eruption, sending super-heated volcanic gas and ash across a large portion of the United States, destroying hundreds of square miles of forest, and killing 57 people in what was the most destructive volcanic eruption in the United States.

Today, over a quarter century later, life is starting to return to the barren landscape surrounding the mountain. However, as the recent steam eruptions starting in October 2004 have illustrated, the danger of another catastrophic eruption is ever present. Visiting Mount St. Helens National Volcanic Monument is to simultaneously witness the result of catastrophic destruction and see the result of rebirth.

Landscape

Mount St. Helens is a typical "stratovolcano," the volcanic form most familiar from photographs of their typically conical profiles. The great 1980 eruption destroyed most of the volcanic cone, leaving a huge amphitheater on the north side that is well seen from the Johnston Ridge observatory/visitor center. Current (2004-5) volcanic activity is building a new lava dome within this amphitheater, visible from the "VolcanoCam" at the observatory (see under "External links") but not yet large enough to replace the destroyed cone.

St. Helens is still glaciated to some extent, despite its reduced altitude. One unexpected and remarkable bit of landscape on the mountain is the astonishing Loowit Falls, a waterfall that emerges directly from the amphitheater bearing meltwater from a glacier within the crater. This falls can be seen (use binoculars) from the observatory, but to get the best feeling for the incongruity of the falls -- it seems to emerge as though from the surface of the moon -- requires a hike on a trail that is closed as of 2005 owing to the volcanic activity.

Attractions

Along Washington 504 are three visitor centers. All three include theatre presentations, exhibits, and information desks:
 • Mount St. Helens Visitor Center at Silver Lake: This visitor center, operated by Washington State Parks, is located about 5 miles east of Castle Rock. It provides visitors with an introduction to the history of the area. Open daily, 9:00 AM - 4:00 PM, closed New Years, Thanksgiving, and Christmas days.
 • Coldwater Ridge Visitor Center: Located about 43 miles east of Castle Rock within the Monument boundaries. Interpretive talks available. Open Thurs-Mon, 10:00AM - 4:00PM, closed December 25-28 and January 1-4.
 • Johnston Ridge Observatory: Located about 52 miles east of Castle Rock, within the blast zone, this observatory provides good views of the north face of the volcano. Interpretive talks available. Open summer months only.
 • Monument passes can be purchased at any of the three visitor centers.

Stay safe

Volcano safety is, to put it mildly, a controversial subject. Compared to many other active volcanoes, Mount St. Helens has been studied particularly extensively, and therefore has a relatively well-defined "safety envelope" that allows informed decision making as regards trail closures, etc. Even St. Helens, however, is prone to bouts of unexpectedly violent behavior, as for example on 8 March 2005 when an explosive event sent ash and steam to elevations above 35,000 feet (10 km) essentially without warning. The monument, therefore, has established a policy regarding road and trail closures that at first glance appears unnecessarily conservative -- but it is not. Believe it. The closures aren't there simply to inconvenience and irritate you. If a trail is closed due to eruptive hazard, stay off the trail.

Other than the volcanic activity, St. Helens poses basically the usual set of hazards associated with mountainous country -- changeable weather, potential for road closures due to snow in the winter, etc. One extra thing to be aware of is that much of the area on the north side of the mountain, particularly the northeast, does not yet have many travel services, even things as basic as gas stations. When leaving the main roads to head for the observatory, or particularly the Windy Ridge viewpoint and trailhead, it's wise to have a full gas tank.