Mount St. Helens National Volcanic Monument Overview

Mt. St. Helens

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On May 18, 1980, the long-dormant Mount St. Helens erupted. Shaken by an earthquake measuring 5.1 on the Richter scale, the north face of this tall, symmetrical mountain collapsed in a massive avalanche of rock debris. Within moments, this slab of rock and ice slammed into Spirit Lake, crossed a ridge 1,300 feet high, and roared 14 miles down the Toutle River. The eruption lasted nine hours, but Mount St. Helens and the surrounding landscape were dramatically changed within moments. A vast, gray landscape lay where once the forested slopes of Mount St. Helens grew.

Carved out of the Gifford-Pinchot National Forest in 1982, the 110,000-acre National Volcanic Monument allows scientists and visitors to see the changes in the landscape and the volcano. Within the monument's bounds, the environment is left to respond naturally to the disturbance. Observe how surviving plants and animals rise out of the ash, colonizing plants catch hold of the earth, and birds and animals find a niche in a different forest on the slopes of Mount St. Helens.

Surround Yourself with Lava
Some 1,900 years ago, a channel of smooth-flowing, pahoehoe lava burst from Mount St. Helens and crusted over. When the eruption ended, the lava either drained out or eroded downward, leaving behind Ape Cave, the largest contiguous lava tube (2.5 miles) in the Western Hemisphere. Cave visitors will pass by lava stalactites, or "lava-sicles," created when hot gases trapped in the tube re-melted the walls and ceiling. One cooled ball of lava floated down the tube's flow until it got stuck between two ledges; the lava drained and left it perched ten feet overhead. In a subsequent eruption, mudflow deposited sandy, volcanic debris in the tunnel; water dripping into the cave has swept away sediment and left behind "sand castles."

Look into the Volcano
Ready to scale Mount St. Helens? Try the Monitor Ridge Route. This non-technical route gains 4,500 feet in five miles to the crater rim (8,365 feet). Although strenuous, Monitor Ridge is suitable for people in good physical condition who are comfortable scrambling on steep, rugged terrain—i.e. blocky lava flows, loose pumice, and ash. Most climbers complete the round trip in 7 to 12 hours. Take great care, as portions of the already precipitous rim may be unstable at any time of the year, and it's nearly 2,000 feet to the crater floor. Don't think about climbing inside, either: Entry into the crater is strictly prohibited (this is an active volcano, after all).

Tread a Land Reborn
Visitors to the monument's rugged and spectacular Mount Margaret Backcountry can observe firsthand the landscape's rebirth and renewal. During the 1980 eruption, the lateral blast—a hot stone-filled wind—shattered trees and swirled around peaks and basins as it toppled thousands of acres of pristine forest. Now hikers may once again explore the 200-some trails that lead to sapphire lakes, pinnacle-studded ridges, and flowered mountain slopes. Ape Canyon Trail (ten miles round-trip) passes along the edge of a large mudflow and offers magnificent views of Mount Adams. Lava Canyon Trail (six miles round-trip) showcases Muddy River as it carves away at the rugged landscape, plummeting 1,400 feet down Lava Canyon's ancient rock.

More on hiking in Mount St. Helens National Volcanic Monument