Mount St. Helens

Mount St. Helens, located in southwestern Washington about 50 miles northeast of Portland, Oregon, is one of several lofty volcanic peaks that dominate the Cascade Range of the Pacific Northwest; the range extends from Mount Garibaldi in British Columbia, Canada, to Lassen Peak in northern California. Geologists call Mount St. Helens a composite volcano (or stratovolcano), a term for steepsided, often symmetrical cones constructed of alternating layers of lava flows, ash, and other volcanic debris. Composite volcanoes tend to erupt explosively and pose considerable danger to nearby life and property. In contrast, the gently sloping shield volcanoes, such as those in Hawaii, typically erupt nonexplosively, producing fluid lavas that can flow great distances from the active vents. Although Hawaiian-type eruptions may destroy property, they rarely cause death or injury. Before 1980, snow-capped, gracefully symmetrical Mount St. Helens was known as the “Fujiyama of America.” Mount St. Helens, other active Cascade volcanoes, and those of Alaska form the North American segment of the circum-Pacific “Ring of Fire,” a notorious zone that produces frequent, often destructive, earthquake and volcanic activity Travel Advice in USA. Some Indians of the Pacific Northwest variously called Mount St. Helens “Louwala-Clough,” or “smoking mountain.” The modern name, Mount St. Helens, was given to the volcanic peak in 1792 by Captain George Vancouver of the British Royal Navy, a seafarer and explorer. He named it in honor of a fellow countryman, Alleyne Fitzherbert, who held the title Baron St. Helens and who was at the time the British Ambassador to Spain. Vancouver also named three other volcanoes in the Cascades–Mounts Baker, Hood, and Rainier–for British naval officers.

History of Mount St. Helens

On May 18, 1980, Mount St. Helens, Washington, exploded in a spectacular and devastating eruption that brought the volcano to the attention of the world. Few people realized that Mount St. Helens had long been the most active volcano in the Cascade Range of the Pacific Northwest. It has a rich and complex 300,000-year history and has produced both violent explosive eruptions of volcanic ash and pumice and relatively quiet outpourings of lava. The volcano’s edifice was mostly built by lava domes and flows from numerous eruptions. Using evidence in these lavas and other deposits, U.S. Geological Survey (USGS) scientists have documented dozens of major individual eruptions of the volcano.An extensive apron of ash and fragmented volcanic rocks surrounds Mount St. Helens and mostly fills the valleys draining its slopes. This material was transported by pyroclastic flows (searingly hot flows of ash and volcanic gases), lahars (volcanic mudflows), and debris avalanches (landslides). Farther away from the volcano, pumice and ash that fell during explosive eruptions form layers that bury the landscape to depths of 10 feet or more.

The pre-1980 eruptive history of Mount St. Helens is strongly episodic. Volcanologists have recognized and named four episodes of volcanic activity, called “stages”– Ape Canyon, Cougar, Swift Creek, and Spirit Lake–separated by dormant intervals. The youngest stage, Spirit Lake, is further subdivided into six eruptive periods. Because the preservation of deposits and other geologic evidence is best for the youngest stages, the farther scientists look back in time the less detail they can infer for the history of volcanism at Mount St. Helens.

Geography of Mount St. Helens

Compared to other volcanoes in the Cascades, Mount St. Helens is fairly young geologically speaking because it formed only 40,000 years ago. Its top cone that was destroyed in the1980 eruption began forming only 2,200 years ago. Because of its quick growth, many scientists consider Mount St. Helens the most active volcano in the Cascades within the last 10,000 years.
There are also three main river systems in the vicinity of Mount St. Helens. These rivers include the Toutle, Kalama and Lewis Rivers. This is significant because the rivers (especially the Toutle River) were impacted in its eruption.The nearest town to Mount St. Helens is Cougar, Washington, which is around 11 miles (18 km) from the mountain. The rest of the area is surrounded by the Gifford Pinchot National Forest. Castle Rock, Longview and Kelso, Washington were also affected by the 1980 eruption however because they are low-lying and near the region’s rivers. The nearest main highway in and out of the area is State Route 504 which connects with Interstate 5.

Post-Eruption Natural Rebound

What was once an area that was completely scorched and knocked down by the eruption is today a thriving forest. Just five years after the eruption, surviving plants were able to sprout through the build-up of ash and debris. Since 1995, there has been a growth in the variety of plats within the disturbed area and today, there are many trees and shrubs growing successfully. Animals have also returned to the region and it is again growing to be a diverse natural environment. Mount St. Helens is a Adventure Place For Vacations.

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