Mt St Helens, a volcano in Washington State, had a huge eruption on May 18, 1980. The damages were over a billion dollars, and 57 people lost their lives. While it was not the worst volcanic eruption on record, it still was a shock. More than a couple of installment loans went into cleaning up, and Mt St Helens has been watched closely since.
The Mt St Helens Eruption
Mt St Helens had been dormant for over a century, but started having earthquakes in March of 1980. For the next two months, the mountain was closely monitored. An earthquake with a magnitude above 5 on the Richter scale hit the volcano. A landslide on the north face opened a vent to the interior. The side of the mountain exploded, sending super heated gases, magma, rock and other debris out of the side of the volcano.
The explosion
The pyroclastic (volcanic) blast that ripped through the side of the mountain as a result of the landslide reached the speed of sound. The debris was shot 20 miles out of the side. Pyroclastic flows (material pouring out of the mountain) continued after the eruption, and 17 were observed afterward. The pyroclastic flows were nevertheless over 800 degrees Fahrenheit in temperature two weeks later.
The damage
A 20 mile swath of destruction flowed straight out of the volcano. Mud flow and debris flows clogged river systems, causing floods and causing extensive damage to river systems. Over a cubic mile of material was shot out of the volcano. A total of 57 people died; 200 homes, 27 bridges, 15 miles of railroad track and 185 miles of highway were destroyed. President Carter compared the desolate wreckage to a lunar landscape when he surveyed it.
Further fallout
An ash cloud was shot 12 miles to the atmosphere. Washington state was blanketed by ash fall, and by May 19, ash had covered Yakima. The city of Spokane, almost 300 miles away, had all visibility reduced to 10 feet, and was plunged into a primordial darkness by the ash. Ash fell as far south as New Mexico and as far east as Minnesota. Airports were forced to ground flights as a result, like the recent Iceland volcano eruptions did. The eruption released almost 1,600 times the heat energy released by the Hiroshima blast. The mountain lost over 1,000 feet in height, and a crater was created almost 2. Since the eruption, some smaller eruptions have taken place. Over $ 1 billion in damage was done by the Mt St Helens eruption. For all her beauty and bounty, Mother Nature is indeed the harshest of mistresses at times.
Citations
Mt St Helens
http://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens
