The large continents of North America and South America are located in the Western Hemisphere. The United States of America is situated within North America. Canada is our neighbor to the north. Our neighbor to the south is Mexico.
The United States of America is home to 50
states and the District of Columbia. As a 21st century resident of Washington and the United States of America, we should feel very fortunate.
As American citizens we enjoy a comfortable
and secure life in this great nation. Washington is located in a small region of the United States known as the Pacific Northwest.
The Pacific Northwest includes the states of
Washington, Oregon, and Idaho. The Canadian province of British Columbia is our neighbor to the north. Washington’s southern neighbor is the state of Oregon. The Pacific Ocean serves as the western boundary. Lying east of Washington is the state of Idaho.
Washington is a medium-sized state that covers just over 70,000 square miles. Washington is one of the smallest states west of the Mississippi River. Did you know Washington is larger than any state east of the Mississippi River?
Washington measures 370 miles from east to west. It is 240 miles between the northern and southern borders.
For hundreds of thousands of years Washington was void of humans. Only recently have humans settled and lived here.
Archaeologists estimate that humans have lived
in the area for at least the last 14,000 years. Today our state's population exceeds six million people. Washingtonians have always depended on the area's natural landscape. Many, in fact, depend on it for their survival!
Why is our landscape so critical to our way of
life and survival? What created our state’s diverse landscape? How do these forces work? Are they still at work today? We will explain the answers to these questions and more. Let us begin with the forces that created our landscape.
Earth’s age is approximately five billion years
old. Humans are believed to have lived on Earth for only the past six million years. Six million years is less than eight hundredths of one percent (8/100) of five billion years! To put this in perspective, it would be like using the 24 hours of a clock to represent Earth's history with each second representing a year. The total number of
seconds (86,400) per day would represent five billion years. Humans have lived on Earth for only 72 of those seconds, or just over one-minute.
Washington residents have only witnessed
2/10ths of one second of our “history clock.” How has our physical environment changed?
Plate movement has greatly affected the landscape of Washington. In fact, plate activity is just as common now as ever before. Millions of years ago, waves from the Pacific Ocean once crashed against the western edge of the Rocky Mountains. This means that where you now live was once an ocean sea floor. The North American Plate continued to move west. As a result, the western portion of North America began to
A smaller oceanic plate played a big role in
changing western Washington. We refer to it as the Juan de Fuca Plate. As it moved under the North American Plate, it pushed the lighter continental plate upward. Mountains rose where once an ocean teamed with life. Volcanic peaks erupted and covered the land with ash and lava.
The area between the Rockies and the Cascades
cracked and allowed lava to flow over the area. Rivers filled with water from melted snow. Flooded rivers flowed to the ocean now hundreds of miles away. Then vast sheets of ice covered and scarred the lower elevations.
Earth’s crust moves in three different ways.
Plate movement occurs in either a divergent, transformant, or convergent fashion. Divergence
is when two giant plates pull apart. This type of crust movement usually occurs on the ocean floor. It is the result of the Earth's crust pulling apart from a central ridge.
Transformant movement occurs when two
plates collide. This collision produces either a sliding or slipping action. This is happening on the famous San Andreas fault in California. Another type of ransformant movement is when two continental plates collide. This is happening in Asia. The Himalayas were formed by this type of plate movement.
The last type of crust movement is convergence. Convergence is when two giant plates meet and one is forced under the other. Convergence is happening beneath Washington.
Over millions of years, the North American
Plate has slowly moved west. Along its way it picks up landforms such as islands and river deltas. This adds weight to the leading edge of the plate. The additional weight slows the land behind the leading edge. The weight causes the continental plate to tilt, uplift, and fold the crust.
This exact force is forming the Cascade
Mountains. The Cascades are the major landform
in Washington. This added weight on the North American Plate is forcing the heavier Juan de Fuca Plate
into the mantle. The heavy oceanic plate is always pushed into the mantle. The oceanic plate also melts as it sinks. The melted rock rises through cracks in the crust above to create volcanoes. Volcanoes are just one of
many processes used to release the pressure within Earth's crust. All this is happening beneath our state. Isn’t it amazing!
The most visible natural force affecting Washington is volcanic activity. The most recent volcanic eruption in the Cascades happened in the spring of 1980. Before the eruption of Mount St. Helens, many scientists were excited about the renewed rumblings of Washington's volcano.
There were also concerns about the potential
damages an eruption could cause. How right they were to be excited and concerned!
Before her eruption, Mount Saint Helens was one of the most beautiful volcanoes in the world. Mount Fuji in Japan is also a volcano of similar beauty. On the morning of May 18, 1980, Mount Saint Helens drastically changed her appearance in the blink of an eye.
Mount Saint Helens violently awoke from
her nap. Geologically speaking, her nap was short — only a hundred years or so. Most volcanoes experience much longer periods between eruptions. When a volcano is inactive, it is said to be dormant. Dormancy is the word used to describe the time between eruptions. Mount Saint Helens ended her dormancy on a beautiful Sunday morning. The blue skies darkened when an earthquake triggered a landslide on the mountain's north face. The entire north face of the mountain instantly slid into the North Fork of the Toutle River. Internal pressure
that had been increasing for two months suddenly was released. The eruption blew a column of ash more than 80,000 feet into the sky.
Within thirty seconds, 1,300 feet of Mount
Saint Helens' peak was gone. Water from the mountain’s melted snow and ice rushed into the rivers carrying rocks, trees, and mud. Wind rushed outward snapping trees and leveling the forest for miles. Wind, high in the atmosphere, also pushed the rising ash east. Cities such as Yakima, Wenatchee, and Moses Lake were covered in ash as day turned into night!
Mount Saint Helens’ shape was instantly changed. Her nearly perfect volcanic cone was gone. Only a barren horseshoe crater was left behind as a reminder of what had been. Mud and debris clogged rivers in southwestern Washington. An unknown number of plants and animals were killed. In addition, 57 people lost their lives.
There are many areas in southwestern Washington where you can see and learn about the devastation of Mount Saint Helens. One is the Johnston Ridge Observatory. There you will gain an appreciation of nature’s power to destroy and create. Years after the eruption, plants and animals are reclaiming their land. You should visit Mount Saint Helens. It is a trip definitely worth your time!
Mount Saint Helens’ eruption created a worldwide interest in our dormant volcanic peaks. Those who live near dormant volcanoes now keep a watchful eye on any activity. As discussed earlier, dormant volcanoes are inactive, or sleeping. Northwest volcanic peaks, such as Mount Rainier, Mount Baker, and Mount Adams are all dormant.
These volcanoes may be dormant, but do not let
them fool you! If any of these volcanoes awaken, Mount Saint Helens’ eruption may prove to have been a walk in the park.
Earlier inhabitants witnessed eruptions of
these dormant volcanoes. Native American folklore and eyewitness accounts described these eruptions. Today, we are wise to learn as much about volcanoes as possible. Hopefully we will be informed to better prepare ourselves for future eruptions.
One example of past eruptions is the Native
American story of the Love Triangle. Their folklore tells about the battle for the love of Loowit. The conflict was between Klickitat (Mount Adams) and Oregon’s Wy’east (Mount Hood). They competed for Loowit’s love. As the story goes, Loowit was once a black, ugly witch who turned into a lovely “Lady of Fire.” Do you
know which volcano the Native Americans called Loowit? If you guessed Mount Saint Helens, your are correct. Do you think the lovely maiden turned back into the black ugly witch on May 18, 1980?
The entire 600 miles of the Cascade Mountains were once extremely active. Continuous volcanic eruptions have built and destroyed the volcanoes. A few destructive volcanic eruptions greatly changed the height
and shape of both Mount Rainier and Mount Saint Helens. Most of the volcanic eruptions occurred long before humans lived in Washington. An eruption long ago covered most of the Pacific Northwest in lava. The lava, however, did not come from a volcano. It flowed
from giant cracks, or fissures, in the crust.
Other Volcanic Activity
Plate movement also causes cracks, called
fissures, in the crust of Earth. These fissures allow magma to flow. This is the type of eruption that created the second largest basalt plateau in the world — the Columbia Plateau. As lava cools it hardens into a type of rock called basalt.
Basalt covers much of eastern Washington and Oregon. This area is called the Columbia Plateau. The plateau was formed over millions of years. The land between the Rocky and Cascade mountains was compressed and cracked. This created fissures. These large fissures allowed lava to erupt and flow in every direction.
More than 55 lava flows cover the Columbia
Plateau. Today, scientists estimate that the basalt may be thousands of feet thick. If you are ever near the Columbia River you can see just a few of the layers in the cliff walls. It is clear that volcanic activity has changed, and will continue to change, our landscape.
Obviously we owe much of Washington's natural beauty and interesting scenery to the heat and pressure beneath us. Eruptions in Washington will continue in the future. We all must realize that we live in the Ring of Fire.
Ring of Fire
Volcanic eruptions and earthquakes are very common around the Pacific Ocean. This area is called the Ring of Fire. The name comes from the many volcanoes and active faults that dominate the area.
One of the largest eruptions in recent history happened in the Ring of Fire on June 12, 1991. The eruption of the Philippine's Mount Pinatubo began with a massive blast. A volcanic plume was pushed more than 11 miles into the sky. The eruption continued for three days. On the third day, a final eruption occurred that was so powerful it destroyed the entire mountain! The heat from the eruption pushed the ash plume more than 25 miles into the atmosphere. The ash went so high that the wind carried it around the entire planet!
The eruption released so much ash and material into the air that it blocked some of the energy from the sun. The average daily temperature of Earth dropped by one full degree the following year. Besides its powerful volcanic eruptions, the Ring of Fire is also known for its earthquakes.
Kobe, Japan was recently devastated by one of
these earthquakes. Of course this earthquake occurred in the Ring of Fire. Kobe-Osaka is Japan’s second-most populated area next to Tokyo. The city of Kobe is Seattle's sister city. Little did residents of Kobe know how their lives would change in just 20 seconds. On Tuesday, January 17, 1995 at 5:46am, an earthquake of 7.2 magnitude on the Richter scale struck the region of Kobe and Osaka. The shallow shock occurred on a fault running from Awaji Island through the city of Kobe. Strong ground movement lasted for about 20 seconds. The Kobe earthquake caused severe damage to buildings, homes, and freeways over a large area. The number of injured reached about 35,000. Nearly 5,500 deaths were confirmed. Some 180,000 buildings were badly damaged or destroyed. Officials estimate that more than 300,000 people were homeless on the night of theearthquake. All this damage was caused by only
20 seconds of shaking ground!
Earthquakes occur when energy in the crust is suddenly and violently released. This energy is usually released from a single point. This point is known as the epicenter. Earthquakes can occur along active faults in
Earth’s crust. Faults occur when two different plates of crust touch. These faults grind and move slowly against each other. Sometimes these faults get stuck. They can remain stuck for decades or even centuries. Finally, the pressure becomes so great that the rock holding the plates suddenly gives way. When it does, the plates
suddenly move. The sudden movement of the
two plates causes the ground to shake or quake.
This is an earthquake.
The largest earthquake ever recorded in
North America happened in Alaska in 1964. Alaska's earthquake measured a whopping 9.2 on the Richter scale. Anchorage, Alaska was the location of the quake’s epicenter. Residents reported strong ground movement for four to five minutes! Compare four to five minutes to
the 20 or 30 seconds of severe ground movement in the Kobe earthquake! The ground in some parts of Alaska was uplifted more than 30 feet in a matter of seconds. Interestingly, more people were hurt from the tidal wave than from the earthquake.
When faults store energy for such long periods, earthquakes like the one in Alaska will happen. Thankfully, earthquakes like this do not happen that often. Over the past 50 years, Washington residents
have experienced three major damaging earthquakes. The most recent earthquake of February 28, 2001 measured 6.8 on the Richter scale. The epicenter of the earthquake was near Olympia. In contrast to the Alaskan quake of 1964, our earthquake had severe ground
movement lasting only 30 to 40 seconds. The earthquake was felt as far away as Utah and British Columbia, Canada. Thankfully, the damage was mostly minor.
Seismologists from around the world have predicted a large earthquake in Washington. They estimate that it will measure between eight and nine on the Richter scale. Most agree that it will occur in the near future. And earthquake this size would be extremely damaging to Washington and the Pacific Northwest.
Earthquakes and volcanic eruptions are not the only forces forming our landscape. Ice has been a major factor in our landscapes formation. The last major ice age was a rather recent geologic event. It ended about 10,000 years ago. During the last ice age, continental glaciers advanced as far south as Olympia and the Columbia River in
Glaciers are formed when snow packs never
completely melt. Over time, the snow pack gets deeper and heavier from new snowfall. Snow is compressed by its own weight. Weight changes the structure of the snow. Snow crystals will start to fit tightly together to form layers of ice. As this ice thickens, its weight increases changing the layers into a solid mass of ice. Gravity begins to move the thickening mass. At the point at which it begins to move, it then becomes a glacier.
Smaller glaciers can even combine to form larger continental glaciers. These glaciers are giant sheets of ice moving across the surface of Earth. They change everything in their path.
These continental glaciers helped create the
landscape of Washington. During periodic ice ages, huge continental glaciers advanced southward from Canada.
Three different lobes of ice pushed into Washington. The three lobes were the Puget, Okanogan, and Polson. The southern edges of these lobes were thousands of feet thick. Erosion and scarring resulted from the movement of these glaciers. It is very easy to see how drastically
Washington's landscape has been affected by
continental ice. Though the ice melted long ago,
the scars they left are everywhere.
The Puget Lobe began its march south from
the Fraser River Valley in Canada. It flowed between the Olympic and Cascade mountains. The lobe advanced as far south as what is now Olympia. As the ice moved, its tremendous weight depressed western Washington. Most of northwestern Washington was covered with thick continental ice. Only the higher mountains remained. Western Washington remained covered in ice for thousands of years.
Glaciers are large conveyer belts of ice. They
easily carry everything in their path, including trees, rocks, dirt, and huge boulders. The material they carry is called glacial till. As the climate began to warm, the Puget Lobe gradually melted. Since it was so large, the
melting took hundreds, if not thousands, of years. When glaciers melt they stall and deposit large amounts of glacial till at the leading edge. This debris formed many of our islands and hills in western Washington. The sheer weight of the glacier also carved our deep waterways. These protected waterways provide Washington with excellent shipping harbors.
The Okanogan Lobe was another portion of the continental ice sheet that moved south into northern Washington. The lobe advanced as far south as the Columbia Basin near Grand Coulee. When the ice reached the Columbia Basin, it blocked the natural course of the Columbia River.
A dam of ice was formed. As the water rose
behind the dam, it flooded the Columbia Basin. The water rushed south, eventually spilling over Dry Falls. This process of glacial flooding continued over thousands of years.
At that time Dry Falls was anything but dry.
It was one of the largest waterfalls in the world. The water rushing over the Columbia Basin dropped hundreds of feet. Dry Falls was once more than 40 times larger than Niagara Falls. Niagara Falls was also formed by the last ice age. Unlike Dry Falls, it still has water rushing over its cliffs today. This constant flooding eroded and scarred the Columbia Basin. These scars are deeply eroded valleys called coulees and are present
today. They truly are impressive sites to see! The most spectacular remnant of the glacial flooding is Dry Falls.
About 10,000 to 15,000 years ago, the Okanogan Lobe began melting. As the lobe melted, the Columbia River burst through the remaining ice. Now that the ice dam was gone, the Columbia River could again flow to the sea on its natural course. When the ice dam broke, the floodwater spilling over the edge of the falls finally stopped. Dry Falls was once again dry.
The lobe continued melting. As the glacial ice melted, it created the river valleys of the Okanogan Highlands. However, the Polson Lobe was not to be outdone by either the Puget or Okanogan lobes.
The Polson Lobe was the third lobe of continental ice to invade the region. As the lobe moved south, it blocked the rivers of western Montana, northern Idaho, and northeastern Washington. Unlike the water behind the ice dam that blocked the Columbia River, this water had no place to go. A huge glacial lake, the
combined size of the Great Lakes, Erie and Ontario, formed behind the ice dam. This lake is now known as Glacial Lake Missoula. The ice dams collapsed nearly every two to three decades. When it finally did collapse, it released a wall of water estimated to be 400 feet
deep. It traveled at a speed of an estimated 65 miles an hour across the Columbia Basin. The erosive force of the water left scars on everything it touched. These scars are what we now call the coulees and Channeled Scablands.
As the water reached the Wallula Gap the flow of water was slowed. The narrow gap acted like a natural dam. The water then filled the area behind the gap. The new lake slowly drained through the gap and
continued to the ocean. This process continued for thousands of years during the last ice age. The amount of water released by Glacial Lake Missoula was amazing. It was equal to more than ten times the combined flow of all the rivers in the world! At that rate, the lake would
have drained in less than 48 hours!
Other Forces of Ice
Alpine glaciers and avalanches continue to erode the slopes of Washington's volcanoes and mountains. Both forms of ice and snow scar the landscape. Avalanches release a sudden burst of destruction. Alpine glaciers are more destructive but much, much slower. Alpine glaciers are common in the higher Cascade and Olympic mountains. Mount Rainier has 26 alpine glaciers covering its slopes.
Two other glacial creations are Lake Chelan
and the Palouse Hills. Lake Chelan is our state's largest and deepest natural lake. It is more than 1,486 feet deep! In contrast, the dry farmland of the Palouse Hills of southeastern Washington and western Idaho were formed by wind blown silt. The silt that formed the hills was left behind by glacial floods. This area is known for its landscape of gently rolling hills.
Wind from the Pacific Ocean picked up and carried very fine particles of glacial till. The soil was blown east until it reached the foothills of the Rocky and Blue mountains. The mountains slowed the wind, and the soil was deposited over thousands of years. Today, the Palouse Hills are extremely fertile because of this soil.
When you look closely, it is easy to see the effects of glaciers everywhere in our state. Some of our northern mountain valleys are scarred. Islands and peninsulas are reminders of continental ice sheets. Mountains and volcanic peaks are blanketed year round in snow and ice.
Some of the most fertile farmland in the world
was even created from ice and wind. These erosive forces obviously have the ability to destroy. However, it is easy to see how they create at the same time. Think of them as Mother Nature's magic paintbrush!
Today, within the state of Washington, there
are many visual reminders of the past. Volcanic peaks, mountain ranges, and a plateau are just a few reminders of Earth's internal violence. Scars in our landscape have been scoured by ice, water, and wind. Washington's numerous physical features are all visual reminders of the power of ice, water, and wind. The next time you see these landforms, you will better appreciate how Earth's fire and ice created and shaped our land. These natural forces are still changing our beautiful landscape.