
Cascade Range-related plate
tectonics
The
Cascade Range (or Cascades) is a
major mountain range of western
North America, extending from southern
British
Columbia
through
Washington
and Oregon
to Northern California. It includes
both non-volcanic mountains, such as the
North Cascades, and the notable
volcanoes known as the
High
Cascades.
The small part of the range in British
Columbia is called the Canadian Cascades or
Cascade Mountains; the latter term is also
sometimes used by Washington residents to refer to the Washington
section of the Cascades in addition to North
Cascades, the more usual American term, as in North Cascades
National Park
.
The
Cascades are part of the Pacific
Ring of Fire, the ring of volcanoes and associated mountains
around the Pacific
Ocean
. All of the known historic eruptions in the
contiguous United States
have been from Cascade volcanoes.
The two most recent were Lassen Peak
in 1914 to 1921 and a major eruption
of Mount St. Helens in 1980
. Minor eruptions of Mount St. Helens have
also occurred since, most recently in 2006.
Geography
At its
southern end the range is about 30 to 50 miles (50 to 80 km)
wide and 4,500 to 5,000 feet (1,370 to 1,520 m) high and 80 miles
(130 km) wide in northern Washington
. At its northern apex at Lytton Mountain
(2,049 m) in Canada
, near the
confluence of the Fraser and Thompson Rivers, the range is only wide, with
its northeasternmost edge being the Nicoamen River
. The tallest volcanoes of the Cascades are
called the High Cascades and dominate their surroundings, often
standing twice the height of the nearby mountains. They often have
a visual height (height above nearby crestlines) of one mile
(1.6 km) or more.
The tallest peaks, such as the 14,411 foot
(4,392 m) high Mount
Rainier
, dominate their surroundings for 50 to 100 miles
(80 to 160 km).
The
northern part of the range, north of Mount Rainier
, is known as the North
Cascades in the United States but is formally named the Cascade
Mountains north of the US-Canada border, reaching to the northern
extremity of the Cascades at Lytton Mountain
, just southwest of the confluence of the Fraser and Thompson
Rivers. Overall the North Cascades and southwestern
Canadian Cascades are extremely rugged, with many of the lesser
peaks steep and glaciated, with valleys quite low relative to its
peaks and ridges, resulting in great local
relief, and major passes are only about 1,000 m
(3,300 ft) high.
The southern part of the Canadian Cascades,
particularly the Skagit
Range
, are geologically and topographically similar to
the North Cascades, while the
northern and northeastern parts - the Coquihalla Range, the name of which is
unofficial, , the northern half of the Hozameen Range
and most of the Okanagan Range
are less glaciated and more plateau-like in
character, resembling nearby areas of the Thompson
Plateau
.
Because
of the range's proximity to the Pacific Ocean
, precipitation is substantial, especially on the
western slopes, with annual accumulations of up to 150 inches
(3,800 mm) in some areas—Mount Baker
, for instance, recorded the largest single-season
snowfall on record in the world in 1999—and heavy snowfall as low
as 2,000 feet (600 m). It is not uncommon for some places in the
Cascades to have over 200 inches (5,500 mm) of snow
accumulation, such as at Lake Helen
(near Lassen Peak), one of the snowiest places in
the world. Most of the High Cascades are therefore white
with snow and ice year-round. The western slopes are densely
covered with
Douglas-fir,
Western Hemlock and
Red
alder, while the drier eastern slopes are mostly
Ponderosa Pine, with
Western Larch at higher elevations. Annual
rainfall drops to 9 inches (200 mm) on the eastern
foothills due to a
rainshadow effect.
Beyond the foothills is an
arid plateau that
was created 16 million years ago as a coalescing series of layered
flood
basalt flows.
Together, these
sequences of fluid volcanic rock form
a 200,000 square mile (520,000 km2) region out of
eastern Washington
, Oregon
, and parts
of Northern California and
Idaho
called the Columbia River Plateau
.
The
Columbia
River Gorge
is the only major break in the American part of the
Cascades. When the Cascades started to rise 7 million years
ago in the
Pliocene, the Columbia River
drained the relatively low Columbia River Plateau. As the range
grew, the Columbia was able to keep pace, creating the gorge and
major pass seen today. The gorge also exposes uplifted and warped
layers of basalt from the plateau.
History

Cascade eruptions in the last 4000
years
Indigenous
peoples have inhabited the area for thousands of years and
developed their own
myth and
legends concerning the Cascades.
According to some of
these tales, Mounts Baker
, Jefferson
, and Shasta
were used as
refuge from a great flood. Other stories, such
as the Bridge of the
Gods tale, had various High Cascades such as Hood
and Adams
, act as god-like chiefs who made war by throwing fire and stone at each other.
St.
Helens
with its pre-1980 graceful appearance, was regaled
as a beautiful maiden for whom Hood and Adams feuded. Among
the many stories concerning Mount Baker, one tells that the
mountain was formerly married to Mount Rainier and lived in that
vicinity. Then, because of a marital dispute, she picked herself up
and marched north to her present position.
Native tribes also
developed their own names for the High Cascades and many of the
smaller peaks, the most well-known to non-natives being Tahoma, the
Lushootseed name for Mount Rainier
.
The legendary and diverse ethnographic history of the Cascade Range
is too complex to recount here, except to say that the spine of the
range forms the divide between the Interior Salish and Coast Salish
language groupings, and mythographically between the realm of
Coyote on the east and that of the Transformers and the
spirit-world of the Coast on the west.
Legends associated with the great volcanoes are many, as well as
with other peaks and geographical features of the range, including
its many hot springs and waterfalls and rock towers and other
formations.
Stories of Tahoma — today Mount Rainier
and the namesake of Tacoma, Washington
— allude to great, hidden grottos with
sleeping giants, apparitions and other marvels in the volcanoes of
Washington
, and Mount
Shasta
in California has long been well-known for its
associations with everything from Lemurians to aliens to elves and, as
everywhere in the Cascades, Sasquatch or
Bigfoot.
In the
spring of 1792 British navigator George
Vancouver entered Puget
Sound
and started to give English names to the high mountains he
saw. Mount Baker
was named for Vancouver's third lieutenant, the
graceful Mount St.
Helens
for a famous diplomat, Mount Hood
was named in honor of Samuel Hood, 1st Viscount
Hood (an admiral of the Royal Navy) and the tallest Cascade, Mount Rainier
, is the namesake of Admiral Peter Rainier. Vancouver's expedition
did not, however, name the range these peaks belonged to.
As marine
trade in the Strait of
Georgia
and Puget
Sound
proceeded in the 1790s and beyond, the summits of
Rainier
and Baker
became
familiar to captains and crews (mostly British and American over
all others, but not exclusively).
In 1805 the
Lewis and Clark
Expedition passed through the Cascades by using the
Columbia River, which for many years was the
only practical way to pass that part of the range. Trade on the
lower
Columbia River did not occur
until after
Lewis and Clark in 1806,
more specifically as a result of
David Thompson's visit on behalf
of the
North West Company shortly
afterwards, and
Simon
Fraser's journey down the
Fraser in
1808.
The
Lewis and Clark expedition, and the many settlers and traders that
followed, met their last obstacle to their journey at the Cascades
Rapids
in the Columbia River Gorge
, a feature on the river now submerged beneath the
Bonneville
Reservoir
.
Before long, the great white-capped mountains that loomed above the
rapids were called the "mountains by the cascades" and later simply
as the "Cascades". The earliest attested use of the name "Cascade
Range" is in the writings of botanist
David Douglas. On their return trip
Lewis and Clark's group spotted a high but
distant snowy pinnacle that they named for the sponsor of the
expedition, U.S. President
Thomas
Jefferson.

Central Washington Cascades
In 1814
Alexander Ross, a fur
trader with the North West
Company, seeking a viable route across the mountains, explored
and crossed the northern Cascades between Fort Okanogan
and Puget Sound. His report of the journey
is vague about the route taken. He followed the lower
Methow River into the mountains.
He might have used
Cascade
Pass
to reach the Skagit River
. Ross was the first European-American to
explore the Methow River area and likely the first to explore the
Stehekin River and Bridge Creek
region. Due to the difficulty of crossing the northern Cascades and
the paucity of beaver, after Ross fur-trading companies made only a
few explorations into the mountains north of the Columbia River
after Ross.
Exploration and settlement of the Cascades
region by Europeans and Americans was accelerated by the
establishment of a major trading post of the Hudson's Bay Company
at Fort
Vancouver
near
today's Portland,
Oregon
. From this base, Hudson's Bay Company
trapping parties traveled throughout the Cascades in search of
beaver and other fur-bearing animals.
For example, using
what became known as the Siskiyou
Trail, Hudson's Bay Company trappers were the first non-natives
to explore the southern Cascades in the 1820s and 1830s,
establishing trails which passed near Crater Lake
, Mount
McLoughlin
, Medicine Lake Volcano
, Mount
Shasta
, and Lassen
Peak
.
The course of political history in the
Pacific Northwest saw the spine of the
Cascade Range being proposed as a boundary settlement during the
Oregon Dispute of 1846.
The United States
rejected the proposal and insisted on the 49th Parallel, which cuts across the range
just north of Mount Baker. Throughout the period of dispute and up
to the creation of the Crown Colony of
British
Columbia
in 1858, the
Hudson's Bay Company's York Factory
Express route, as well the route of fur brigades, followed the
Okanogan River along the east edge of the Cascades and the Columbia
River through the range. Passes across the range were not
well known and little used.
Naches Pass
was used for driving cattle and horses to Fort
Nisqually
.
Yakima Pass was also used by the
Hudson's Bay Company. The vast majority of non-native residents of
the Cascade Range region until about 1840 were British subjects,
most of mixed French-native blood and some Hawaiians and blacks as
well as Scots who were the backbone of Hudson's Bay Company
administration.
American settlement of the flanks of the Coast Range did not occur
until the early 1840s, at first only marginally.
Following the
Oregon Treaty the inward flux of
migration from the Oregon Trail
intensified and the passes and back-valleys of what is now the
state of
Washington
were explored and populated, and it was not long
after that railways followed. Despite its being traversed by
several major freeways and rail lines, and its lower flanks
subjected to major logging in recent decades, large parts of the
range remain intense and forbidding alpine wilderness.
Most of the northern
half of the High Cascades, from Rainier north, have been preserved
by US national or British
Columbia
provincial parks (such as E.C.
Manning Provincial Park
), or other forms of protected area.
The
Canadian side of the range has a history that includes the Fraser Canyon Gold Rush of 1858-60
and its famous Cariboo Road, as well as
the older Hudson's Bay Company
Brigade Trail from the Canyon to the Interior, the Dewdney Trail,
and older routes which connected east to the Similkameen
and Okanagan
valleys.
The
southern mainline of the Canadian Pacific Railway penetrated
the range via the passes of the Coquihalla River
, along one of the steepest and snowiest routes in
the entire Pacific Cordillera. Near Hope,
B.C.
, the railway
roadbed and the Othello Tunnels
, now decommissioned, are popular tourist recreation
destinations for hiking and bicycling. The pass is used by
the Coquihalla Highway, a
government megaproject built as part of
the Expo 86 spending boom of the 1980s,
which is now the main route from the Coast to the British
Columbia
interior. Traffic formerly went via the Fraser Canyon
, to the west, or via Allison Pass
and Manning
Park
along Highway 3 to
the south, near the border.
The
Barlow
Road
was the first established land path for U.S.
settlers through the Cascade Range in 1845, and formed the final
overland link for the Oregon Trail
(previously, settlers had to raft down the treacherous rapids of
the Columbia River). The
Barlow Road left the Columbia at Hood River and passed along the
south side of Mount Hood at Government Camp, terminating in Oregon
City. There is an interpretive site there now at "The End of The
Oregon Trail." The road was constructed as a toll road —
$5/wagon — and was very successful.
In addition, the
Applegate Trail was
created to allow settlers to avoid rafting down the Columbia River.
The
Applegate Trail used the path of the California Trail to north-central Nevada
.
From
there, the Applegate Trail headed northwest into northern
California, and continued northwest towards today's Ashland,
Oregon
. From there, settlers would head north along
the established Siskiyou Trail into the
Willamette Valley.
With the
exception of the 1915 eruption of remote Lassen Peak
in Northern
California, the range was quiet for more than a century.
Then, on
May 18, 1980, the dramatic eruption of little-known Mount St.
Helens
shattered the quiet and brought the world's
attention to the range. Geologists were also concerned that
the St. Helens eruption was a sign that long-dormant Cascade
volcanoes might become active once more, as in the period from 1800
to 1857 when a total of eight erupted.
None have erupted
since St. Helens, but precautions are being taken nevertheless,
such as the Mount Rainier Volcano Lahar
Warning System in Pierce County, Washington
.[11493]
Human uses
Soil conditions for
farming are generally good, especially downwind of
volcanoes. This is largely due to the fact
that volcanic rocks are often rich in
minerals such as
potassium
and decay easily. Volcanic debris, especially
lahars, also have a leveling effect and the storage of
water in the form of snow and ice is also
important. Much of that water eventually flows into
reservoirs where it is used for recreation
before its potential
energy is captured to
generate
hydroelectric power
before being used to
irrigate
crops.
Because of the abundance of powerful streams, many of the major
westward rivers off the Cascades have been dammed to provide
hydroelectric power.
One of these, Ross Dam
on the Skagit River
, created a reservoir which spans the border
southeast of Hope, British Columbia
, extending into Canada two miles.
At the
foot of the southeast flank of Mount Baker, at Concrete,
Washington
, the Baker
River is dammed to form Lake Shannon and Baker
Lake.
In addition, there is a largely untapped amount of
geothermal power that can be generated from
the Cascades. The
USGS Geothermal Research
Program has been investigating this potential.
Some of this energy
is already being used in places like Klamath
Falls, Oregon
where volcanic steam is used
to heat public buildings. The highest recorded temperature found in
the range is 510 °F (265 °C) at 3,075 feet (937 m) below Newberry
Volcano
's caldera floor.
Cascade Range volcanoes
Image:Cascade_Range_map.png|thumb|275px|Major volcanoes in the
Cascade Range (image map)
rect 219
49 360 66 Mount
Baker
rect 387 93 244 77 Glacier Peak
rect 208 160 369 178 Mount Rainier
rect 171 185 329 205 Mount St.
Helens
rect 175 186 207 230 Mount St.
Helens
rect 213 210 378 236 Mount
Adams
rect 203 264 363 294 Mount Hood
rect 201 313 391 342 Mount
Jefferson
rect 202 361 366 386 Three
Sisters
rect 240 395 437 420 Newberry
Volcano
rect 180 434 461 460 Mount Mazama
rect 169 481 366 505 Mount
McLoughlin
rect 205 535 447 566 Medicine
Lake Volcano
rect 172 547 202 590 Mount Shasta
rect 177 569 312 590 Mount Shasta
rect 205 606 339 648 Lassen Peak
Volcanoes south of the
Fraser River in
the
Cascade Volcanic Arc (a
geological term) belong to the Cascade Range
(a
geographic term). Peaks are listed
north to south.
North Cascades
- Coquihalla Mountain
(southern British Columbia) — highest peak in
the Bedded Range.
- Mount Baker
(Near the United States
-Canada
border) — highest peak in northern Washington
. It is an active
volcano. Steam activity from its crater occurs relatively frequently. Mount
Baker is one of the snowiest places on Earth; in 1999 the ski area
(on a subsidiary peak) recorded the world's greatest single-season
snowfall: 1,140 inches (95 feet or 2,896 cm).
- Glacier Peak
(northern Washington) — secluded and
relatively inaccessible peak. Contrary to its name, its
glacial cover isn't that extensive. The volcano is surprisingly
small in volume, and gets most of its height by having grown atop a
nonvolcanic ridge.
High Cascades
- Mount Rainier
(southeast of Tacoma, Washington
) — highest peak in the Cascades, it dominates
the surrounding landscape. There is no other higher peak northward
until the Yukon-Alaska-BC border apex beyond the Alsek River
.
- Mount St. Helens
(southern Washington) — Erupted in 1980,
leveling forests to the north of the mountain and sending ash
across the northwest. The northern part of the mountain was
destroyed in the blast (1980 Mount St. Helens
eruption
).
- Mount Adams
(east of Mount St. Helens) — the second
highest peak in Washington and third highest in the Cascade
Range.
- Mount
Hood
(northern Oregon
) — the
highest peak in Oregon and arguably the most frequently climbed
major peak in the Cascades.
- Mount Jefferson
(northcentral Oregon) — the second highest
peak in Oregon.
- Three Fingered Jack
(northcentral Oregon) — Highly eroded Pleistocene volcano.
- Mount Washington
(between Santiam and McKenzie passes) — a
highly eroded shield volcano. [11494]
- Three Sisters
(near the city of Bend, Oregon
) — South Sister is the highest and youngest,
with a well defined crater. Middle Sister is more pyramidal
and eroded. North Sister is the oldest and has a crumbling rock
pinnacle.
- Broken
Top
(to the southeast of South Sister) — a highly
eroded extinct stratovolcano.
Contains Bend Glacier.
- Newberry Volcano
— isolated caldera with
two crater lakes. Very variable lavas.
Flows from here have reached the city of Bend.
- Mount Bachelor
(near Three Sisters) — a geologically young
(less than 15,000 years) shield-to-stratovolcano which is now the
site of a popular ski resort.
(Mt.
Bachelor ski area
)
- Mount Bailey
(north of Mount Mazama)
- Mount Thielsen
(east of Mount Bailey) — highly eroded volcano
with a prominent spire, making it the Lightning Rod of the
Cascades.
- Mount Mazama
(southern Oregon) — better known for its
Crater
Lake
, which is a caldera formed
by a catastrophic eruption which took out most of the summit
roughly 6,900 years ago. Mount Mazama is estimated to have
been about 11,000 ft. (3,350 m) elevation prior to the
blast.
- Mount
Scott
(southern Oregon) — on the southeastern flank
of Crater Lake. At 8,929 feet (2,721 m) elevation, this
small stratovolcano is the highest peak in Crater Lake
National Park
.
- Mount McLoughlin
(near Klamath Falls, Oregon
) — presents a symmetrical appearance when
viewed from Klamath Lake.
- Medicine Lake Volcano
— a shield
volcano in northern
California which is the largest volcano by volume in the
Cascades.
- Mount Shasta
(northern California) — second highest peak in
the Cascades. Can be seen in the Sacramento Valley as far as 140 miles
(225 km) away, as it is a dominating feature of the
region.
- Lassen Peak
(south of Mount Shasta) — southernmost volcano
in the Cascades and the most easily climbed peak in the
Cascades. It erupted from 1914 to 1921, and like Mount
Shasta, it too can be seen in the Sacramento Valley, up to 120
miles (193 km) away.
Protected areas
There are four
U.S. National Parks in the Cascade Range and
many
U.S. National Monuments,
U.S. Wilderness Areas, and
U.S. National Forests. Each classification
protects the various
glaciers, volcanoes,
geothermal fields, rivers,
lakes, forests, and wildlife to varying degrees.
National parks
National monuments
Provincial Parks
Wilderness areas
Ecology

Red Huckleberry near Crater Lake
There is a wide range of flora and fauna inhabiting the Cascade
Range. The southern part of the Cascades are within what
Conservation International
defines as the
California
Floristic Province, an area of high
biodiversity. There are numerous species of
trees, shrubs and other flowering plants, as well as a gamut of
mammals,
avifauna,
amphibians and
reptiles.
See also
References
Notes
Sources
External links