Mt St Helens Eruption: 30th Anniversary: 1980 Volcano Video
Mt. St. Helens 30th Anniversary: Mount St. Helens Volcano Erupted May 18, 1980 (video)
For those living in the Pacific Northwest a reminder that May 18th is the 30th anniversary of the the eruption of Mt. St. Helens is not required.
An eruption column rose 80,000 feet (24,400 m) into the atmosphere and deposited ash in 11 U.S. states. At the same time, snow, ice and several entire glaciers on the volcano melted, forming a series of large lahars (volcanic mudslides) that reached as far as the Columbia River, nearly fifty miles (eighty kilometers) to the south. Less severe outbursts continued into the next day only to be followed by other large but not as destructive eruptions later in 1980.
Of course, the eruption was covered extensively in the news but one thing some may forget is the warnings scientists had prior to Mount St. Helens erupting. There was intense seismic activity in the the Pacific Northwest.
A total of about 10,000 earthquakes were recorded prior to the May 18 event...Visible eruptions ceased on May 16, reducing public interest and consequently the number of spectators in the area. Mounting public pressure then forced officials to allow 50 carloads of property owners to enter the danger zone on May 17 to gather whatever property they could carry.
Then on 8:32:17 am local time a final earthquake with a magnitude of 5.1 triggered a massive slide on the north face of Mount St. Helens
One of the largest landslides in recorded history, the slide travelled at 110 to 155 miles per hour (175 to 250 km/h) and moved across Spirit Lake's west arm; part of it hit a 1,150-foot (350 m) high ridge about 6 miles (9.5 km) north. Some of the slide spilled over the ridge, but most of it moved 13 miles (21 km) down the North Fork Toutle River, filling its valley up to 600 feet (180 m) deep with avalanche debris. An area of about 24 square miles (62 km²) was covered, and the total volume of the deposit was about 0.7 cubic miles (2.9 km³).
Fortunately, scientists convinced officials to shut down the area around Mount St. Helens prior to the eruption thereby saving thousands of lives. Fifty-Six people were killed, Two hundred homes were destroyed, miles of railways and roads were completely wiped out. In total the 1980.
In all, Mount St. Helens released 24 megatons of thermal energy, 7 of which was a direct result of the blast. This is equivalent to 1,600 times the size of the atomic bomb dropped on Hiroshima.
Mount St. Helens eruption recovery costs were around $1.2 Billion.
The video shown is actually a series of photographs taken by Gary Rosenquist who was camping 11 miles away from Mt. St. Helens when the eruption occurred. His camping party was saved because the geography of the nearby terrain kept the lava at bay.
Video: Mt. St. Helens Eruption: May, 18 1980