  Mount St. Helens reflected in Spirit Lake. May 19, 1982 View Photos Summary Mount St. Helens is a stratovolcano in the Cascades range of mountains in southwest Washington State and is the most active volcano in the continental United States. In 1982 The President and Congress designated over 110,000 acres as Mount St. Helens National Volcanic Monument after the catastrophic eruption in 1980. Earthquake activity at Mount St. Helens was not monitored by seismologists until seismometers were installed near the volcano in 1972. From January 1975 through early 1980 only 44 earthquakes were located within 35km (22mi) of the volcano. The last volcanic activity in the continental US had ocurred in 1912 with an eruption of Mt. Lassen in California. A sleeping giant awakens... Mount St. Helens started rumbling on March 15, 1980, when a period of low-level seismic activity began. On March 20, 1980 a magnitude 4.1 earthquake, unlike any that had been previously detected ocurred just northwest of the summit of Mount St. Helens. Sesimologists were uncertain whether these quakes were related to volcanic activity. They decided to deploy addtional seismic monitoring equipment to better undertstand the activity. This was the first hint that there may be volcanic activity. On March 21 Earthquake activity increased. University of Washington seismologists warned the US Forest Service that continued ground shaking from sizeable earthquakes could cause new avalanches. Although seismologists were suspicious the earthquakes might be related to volcanic activity, they did not say so publicly. Up to this point the only hazard warnings raised were of avalanches. Unlike a typical aftershock sequence in which the number of earthquakes decreases with time, the number of earthquakes following the 4.1 earthquake on March 20 increased. Scientists were uncertain as to whether or 
not the earthquakes would lead to renewed volcanic activity. By March 24,
however, they became convinced that the current earthquake sequence could be
a precursor to renewed eruptive activity at Mount St. Helens. On March 27
their suspicions were confirmed when Mount St. Helens began a sequence of
phreatic explosions that would continue intermittently until May 14.
On March 30, 1980 93 explosions of steam, gas, and ash were observed. There were 58 earthquakes of magnitude 3.0 and greater, with 6 larger than 4.0. By this time there were several craters at the summit of the mountain caused by the various explosions. By early April these craters coalesced into once crater 1700 feet long, 1200 feet accross and 500 feet deep. The rest of peak was fractured and cracked.  From early April to May 17 rising pressure built a "bulge" on the north
side of Mount St. Helens as magma pushed up within the peak. Angle and
slope-distance measurements to the bulge indicated it was growing at a rate
of up to five feet (1.5 meters) per day.
By late April the explosions all but ceased. The volcano appeared to the public as quiet. Seismologists and volcanologists were very concerned about the seismic activity as the bulge building on the north side of the mountain continued. On April 29, 1980 Washington state officials asked the governor to close a large area around the volcano. Officials were frustrated because the public was largley unaware of the potential dangers. By May 17, part of the volcano's north side had been pushed upwards and outwards over 450 feet (135 meters). Eruption! 
At 8:32am on Sunday, May 18, 1980 a 5.1 magnitude earthquake ocurred 1 mile
under Mount St. Helens. The north slope of the mountain, weakened by the
bulging pressure, gave way and a large explosion blew outwards to the north
causing the largest landslide in recorded history, moving 250 million cubic
yards of dirt, ash and steam with a temperature up to 350oC. The glaciers and ice on the top of the near 10,000'
mountain melted instantly and formed large lahars and pyroclastic flows
which choked the Toutle River and downstream to the Columbia. So much ash
and rock choked the Columbia River that 18 ships were trapped
upstream. From my own eyes... To some degree I was a witness to these events: From Portland OR. I felt a slight rumble in the ground and heard a muted bang from the north. Looking north I could see a plume of ash and steam over 20,000' in the sky. Global Effects This eruption was not a local event. The ash plume presented a hazard to traffic in a busy air traffic corridor and measurable ashfall was found across North America. The steam and ash cloud, which towered over 80,000 feet circled the planet in 10 days. This affected weather patterns globally for years to come. Within half an hour of the explosion ash was falling on Portland, despite the ENE wind direction at the time. In contrast the city of Yakima,WA, on the other side of the cascades from the volcano was burried in ash. Day became night. The awakened giant has not gone back to sleep... Since May 18, 1980 there have been tens of thousands of seismic events, including dome building in 1986, eruptions of ash and steam, and occasional pyroclastic flows and lahars. In Septeber of 2004 seismic activity at Mount St. Helens increased sharply with thousands of earthquakes, some reaching magnitude 4, between September and October of 2004. On October 1, 2004 a steam and ash explosion ocurred. Between October 1-6 several small steam and ash events ocurred. October 6 began the current eruptive event with gas ash and steam explosions and new lava dome building. This lava dome has grown beyond the size of the 1986 dome and if building continues at the current rate the mountain will surpass its original height of 9,677 feet in seven years. This latest event is considered on-going by USGS, UW and other federal officials. Officials have not ruled out explosive eruptions similar to the catastrophic eruption of 1980, however, given the structure of the mountain as it sits, these eruptive events, however unlikely, would most certainly be vertical explosions throwing ash and steam into the air, and throwing rocks within several miles of the existing crater. This type of eruption is considered very unlikely. The May 18, 1980 explosion was a lateral blast which sent material northward and outward because of built up pressure. The current eruptive event is showing pressure releases vertically which is very different from the 1980 blast. Glaciers
New Life 
After the 1980 eruption the immediate surrounding area of the crater was
covered in ash, ejected rock -- primarily pumice, and pyroclastic flows.
Everything that was there was buried alive. In this death, however, came new
life.The Pocket Gopher  The palm size pocket gopher doesn't know he plays an important role in the
remergance of life in the barran blast area. These rodents bury themselves
under the ash in the winter and feed on underground plant parts, and brings
up furtile soil from the tunnels they dig. This soil becomes seed bed for
new vegetation.
Elk Surprisingly, elk were seen on the landslide deposit west of the volcano only weeks after the main 1980, eruption. In recent years, as  more plant life emerges, these large relatives of deer move throughout the
blast zone, feeding in the valleys in winter and moving to the higher slopes
in the spring and summer. As they climb steep slopes, their hooves erode the
volcanic debris, uncovering soil and speeding the return of plants. New
vegetation forms from the seeds carried in the waste of the elk.
The Mountain Blue Bird  These small, colorful birds take nest in the fallen trees from the main
blast. These birds prefer open areas where they feed on insects. The blue of
these birds stands out in sharp contrast to the ashen surroundings.
Fireweed  From seeds that float like
parachutes in the wind, these hearty hearty plants send
out roots that can reach fertile soil below the sterile volcanic ash. By
mid-summer the slopes and ridges near the volcano abound with the flaming
pink flowers that appear in clusters along a stem. As the plants die back in
the fall their leaves and stems collect on the ash providing organic matter
for the creation of new soil. -- Excerpt from: USFS, 1998, Volcano Review:
U.S. Forest Service, Summer/Fall 1998.
A shift in perspectives Animal life from small insects to large elk appear to be having a strong influence on the desolate surroundings. Animals are colonizing areas on the basis of habitat charactaristics and help to shape habitat structure and composition. Plant life from all stages of forest development appear to be cropping up simultaneously. This contradicts classic ecological theory that describes the orderly establishment and successive replacement of one group of plants by another (for example, mosses followed by grasses by shrubs by trees). Classic theory, based upon studies of abandoned fields and formerly glaciated terrain, does not appear to apply at Mount St. Helens. Mount St. Helens National Volcanic Monument is in the Gifford Pinchot National Forest near Castle Rock, WA. The closest major cities to the monument are Seattle/Tacoma, WA., and Portland, OR. While visiting this national monument and park please remember to take only pictures and leave only footprints. Mount St. Helens has a stark beauty. Its surrounding landscape is some of the newest meadow and forestland in the world. New life has sprung where old life was destroyed. There are still thousands of acres of trees blown over during the 1980 eruption. Viewing the mountain in spring and autumn affords the viewing of a snow-capped crater. From the Johnston Ridge visitor center the inside of the crater, lava domes and glacier is visible. With all the ash and rock fall during the current eruption the glacier is a very dirty gray mass of ice, rock, and ash. When traveling to see Mount St. Helens take into account that it is an active volcano and as such there may be hazards to life and property. During the last year the Forest Service and USGS have weighed these hazards and determined where road closures, if any, are needed. The most likely hazard is ashfall which can cause difficulty in breathing, particularly in very young children, the elderly, and people with asthma or other breathing disorders as well as damage to automotive carburators, fuel injection manifolds, turbo chargers and other automotive damage. It is a good idea to check weather and the status of the volcano before going. The visitor centers are:
The state highway to the visitor centers, WA-504, is the highest state maintained highway and as such it is also a good idea to bring food, water and blankets and/or other warm clothing in case of bad weather or volcano hazards. During the winter, WA-504 will be maintained and plowed by Washington State Department of Transportation. Please drive cautiously while plows are present and plowing. In case of ashfall: Do not breathe ash! Cover your nose and mouth with a handkerchief or shirt, or anything that can help filter out ash. If you are in your vehicle, stay there and close your windows! If the engine is running find a safe place to park and turn off your engine. If you are inside a building, stay there, otherwise make your way to your car or the nearest building (other than outdoor toilet facilities) and stay there until the air clears or you are evacuated by emergency personnel. Under most conditions ash clouds will dissipate within 5 minutes and completely disappear in 30 minutes. In the event of major ashfall (3mm on ground and higher) there is increased risk to engine components. Vehicles can stir up ash clouds while driving on ash covered roads. Dry road conditions become slippery, wet road conditions are worse. In wet weather with ash on the pavement braking ability is greatly reduced. Visibility can be only a few feet. Driving in these conditions is dangerous and should be done very carefully. To get to Mount St. Helens from Portland: Take I-5 north to Exit 49: WA-504 (Spirit Lake Hwy) Continue east on WA-504 to Johnston Ridge. There are three visitor centers along the way. To get to Mount St. Helens from Seattle/Tacoma: Take I-5 south to Exit 63: WA-505 (Toledo-Winlock Rd.) south to WA-504. Turn left on WA-504 and follow east along to Johnston Ridge. There are three visitor centers along the way. From points east: (I-90): Take I-90 west to North Bend. Exit at SR-18 and follow through Auburn and merge with I-5 south in Federal Way. Continue on I-5 south to WA-505 (Toledo-Winlock Rd.) south to WA-504. Turn left on WA-504 and follow east along to Johnston Ridge. There are three visitor centers along the way. Map to Mount St. Helens While there are some forest service roads near and around Mount St. Helens the last information I had was that these roads are closed and access to the crater is restricted to USFS/USGS personnel. The USFS Mount St. Helens website is a great resource for local information about the volcano and surrounding national monument and forest.
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