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A Very Much Alive and Still Dangerous Volcano.
The May 18, 1980, eruption of
Mount Saint Helens was the deadliest and most powerful volcanic eruption
in the recorded history of North America.
 The
eruption, instantly blasted the top 1,300 feet of the mountain away; a
full cubic mile of earth and rock. This amount of pulverized debris and
ash, could cover New York City’s Manhattan Island to a depth of over 400 feet.
The
force of the Saint Helens eruption was equivalent to 500 atomic bombs
and the mighty roar of the blast was heard by people over 300 miles
away.
Over 200 square miles of forest were
obliterated or flattened like toothpicks. Cabins and cottages as far
away as 20 miles were buried in ash and mud. It is estimated that more
than 175,000 wild and domestic animals were killed.
Tragically, fifty-seven people perished in this incredible natural disaster.
Ash drifted high into the atmosphere and
fell to the east across nine western states and Canada. The
economic devastation totaled over one billion US dollars.
A steam plume rises 3,000 feet into the sky, May 19, 1982 (Photo USGS)
Today, from a vantage point high on Harry's Ridge you can peer into the
gapping crater on the north face of a still potentially dangerous and active Mount
Saint Helens. Plumes of steam, gas and ash occur periodically and
serve as a constant reminder of the potentially lethal forces at work
deep within Saint Helens.
On Johnston Ridge, you can also see into the crater and you are also standing directly in what
is known as the "lateral blast zone." During the 1980 eruption, a 600
mile an hour, super-heated wind instantly blew out of crater and roared
down the mountain slopes, incinerating or flattening
everything in its path for a distance of over 12 miles.
The path of the May 18, 1980 pyroclastic flow (Photo Dr. Von Zuko 1999)
Renewed 2004 volcanic activity resulted in magma reaching the surface
and forming a new lava dome within the crater. On March 8, 2005 a
minor eruption blasted a plume of steam and ash 36,000 feet into the air
that was visible as far away as Seattle Washington.
The 'Whaleback' feature of the new lava dome (Photo USGS)
On October 22, 2006 a 3.5 magnitude earthquake caused a collapse and
avalanche inside the crater that sent an ash plume 2,000 feet over
the western crater rim. On December 19, 2006 a large steam plume
was observed. Mount Saint Helens has been in a state of constant
eruption since 2004.
by:
Dr. Von Zuko 2007©
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Dr. Von Zuko's Top Seven:
The Most Dangerous Volcanoes in the United States.
(Descending order)
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Kilauea,
Hawaii
Currently the most active volcano on earth. It lies against the flank of
the Mauna Loa volcano (see #7)
Mount Saint Helens,
Washington Cascade Range
Mount Rainier,
Washington
Cascade Range
Mount Hood,
Oregon
Cascade Range
Mount Shasta, California
Cascade Range
South Sister, Oregon
Cascade Range
Mauna Loa,
Hawaii
The largest volcano on earth.
Kilauea lava fountain (approx. 10 m high)
USGS Photo.
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