Mt. Rainier and Mt. St. Helens

Mt. Rainier and
Mt. St. Helens
Active in the Cascades
The
Cascade
Mountain
Range
Mt. Rainier
• Located in the Cascade
Mountain Range in
Washington State
• Located about 75 miles
from Seattle around a 2
hour drive
• Highest point in the
state of Washington
14,410 feet high
Seattle, WA
Mt. Rainier
Fun Facts about Mt. Rainier
• an active stratovolcano or composite volcano
• topped by 26 major glaciers; the most famous are
Nisqually, and Emmons Glacier
• climbed by more than 8,000-13,000 people
• An average of 3 deaths happen every year and only
½ of the attempts reaching the summit
Fun Facts Continued
• The most recent recorded volcanic eruption was between
1820 and 1854, but many eyewitnesses reported eruptive
activity in several years after this.
• Mt. Rainier was once named,
Mt. Tacoma…early painting of
Mt. Tacoma, 1888.
• In 1998, the United States Geological
Survey began putting together the Mount Rainier Volcano
Lahar Warning System to assist in the emergency evacuation
of the Puyallup River valley in the event of a catastrophic
debris flow.
Recreational Activities on
Mt. Rainier
• Mountain Climbing: must be educated in wilderness
and glacier traveling and self rescue. It takes usually
2-3 days to reach the summit.
• Camping and hiking the Wonderland
Trail
• Snowshoeing, cross country skiing
and winter sports.
• Spend the night at the historic Paradise Inn.
Mt. St. Helens Today
• Located in the Cascade
Mountain Range in
Washington State
• Located about 90 miles
SE from Seattle around
a 3 hour drive
• Actually located closer
to Portland, OR about
65 miles
Facts about Mt. St. Helens
Before the Eruption
• Mt. St. Helens was 9,677 feet before the eruption. It lost a
total of 1,314 feet due to the eruption.
• Some of the names given to the
mountain were Louwala-Clough
("Smoking Mountain")and the
most commonly used name today
Loo-wit ("Keeper of the Fire").
• Skiing, camping, fishing were popular
activities.
• Skiing near the base of
the mountain
• Mt St Helens Lodge ran
by Harry Truman. Harry,
his 16 cats and the lodge
are now 150 feet or so
under the Spirit Lake
lakebed.
The Eruption of Mt. St. Helens
• Earthquakes begin March 18, 1980;
the largest one March 25th
• 176 aftershocks were registered
within 5 days
• Earthquakes continued into April
and May
• Exploding eruptions of steam begin
on March 27th forming a new 250
foot crater
• A second crater was formed on
March 29 sending ash into the air
forming clouds and causing
lightning
4.5 on the
Richter
Scale
• April and early May this bulge
grew 5 to 6 ft per day, and by
mid-May it extended more than
400 feet north
• Before the May 18th eruption
10,000 earthquakes were
recorded
• 7 a.m on May 18th Volcanologist
David Johnston radios in no
change in any activity
• 8:32 a.m a 5.1 Earthquake
underneath the north slope
triggers part of the volcano to
slide
• One of the largest landslides in
recorded history filling parts of
Spirit lake
• Spirit Lake water was displaced
causing 600 foot waves on the
north shore
• The landslide exposed the
magma in St. Helens' neck to
much lower pressure causing the
gas-charged, partially molten
rock and high-pressure steam
above it to explode a few seconds
after the slide started
• As the avalanche and initial
pyroclastic flow were still
advancing, a huge ash column
grew to a height of 12 miles
(19 km) above the expanding
crater in less than 10 minutes and
spread tephra into the
stratosphere for 10 straight hours
• Ash was carried 60 mph
due to strong winds; it was
carried as far as Denver,
Oklahoma, and Minnesota
• During the nine hours of
vigorous eruptive activity,
about 540 million tons of
ash fell over an area of
more than 22,000 square
miles
• 57 people
were killed and
200 homes were
lost
Soon After the Eruption
Before
After
Mt. St. Helens Recovers