North Cascades National Park
North Cascades National Park is an American national park in the state of Washington. At more than , it is the largest of the three National Park Service units that comprise the North Cascades National Park Complex. North Cascades National Par ...
, in
Skagit County
Skagit County is a county in the U.S. state of Washington. As of the 2020 census, the population was 129,523. The county seat and largest city is Mount Vernon. The county was formed in 1883 from Whatcom County and is named for the Skagit Ind ...
of
Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered o ...
state. It is part of the
North Cascades
The North Cascades are a section of the Cascade Range of western North America. They span the border between the Canadian province of British Columbia and the U.S. state of Washington and are officially named in the U.S. and Canada as the Casca ...
Fred Beckey
Friedrich Wolfgang Beckey (14 January 1923 – 30 October 2017), known as Fred Beckey, was an American rock climber, mountaineer and book author, who in seven decades of climbing achieved hundreds of first ascents of the tallest peaks and best ro ...
, his brother Helmy Beckey, Jim Crooks, Lloyd Anderson and Dave Lind in 1940.Beckey, Fred. Challenge of the North Cascades.
Climate
Forbidden Peak is located in the
marine west coast
An oceanic climate, also known as a marine climate, is the humid temperate climate sub-type in Köppen classification ''Cfb'', typical of west coasts in higher middle latitudes of continents, generally featuring cool summers and mild winters ...
climate zone of western
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...
weather front
A weather front is a boundary separating air masses for which several characteristics differ, such as air density, wind, temperature, and humidity. Disturbed and unstable weather due to these differences often arises along the boundary. For in ...
s originate in the
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...
, and travel northeast toward the
Cascade Mountains
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, a ...
. As fronts approach the
North Cascades
The North Cascades are a section of the Cascade Range of western North America. They span the border between the Canadian province of British Columbia and the U.S. state of Washington and are officially named in the U.S. and Canada as the Casca ...
, they are forced upward by the peaks of the Cascade Range, causing them to drop their moisture in the form of
rain
Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...
or
snowfall
Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes.
It consists of frozen crystalline water throughout ...
onto the Cascades. As a result, the west side of the North Cascades experiences high precipitation, especially during the winter months in the form of snowfall. Due to its temperate climate and proximity to the Pacific Ocean, areas west of the Cascade Crest very rarely experience temperatures below or above . During winter months, weather is usually cloudy, but, due to high pressure systems over the Pacific Ocean that intensify during summer months, there is often little or no cloud cover during the summer.Beckey, p. 16 Because of maritime influence, snow tends to be wet and heavy, resulting in high
avalanche
An avalanche is a rapid flow of snow down a slope, such as a hill or mountain.
Avalanches can be set off spontaneously, by such factors as increased precipitation or snowpack weakening, or by external means such as humans, animals, and ea ...
danger. This climate supports the Forbidden Glacier in the northwest cirque, the immense Boston Glacier to the east, and glacial remnants on the south side in Boston Basin. These glaciers carved Forbidden Peak into a classic horn.
Geology
The North Cascades features some of the most rugged topography in the
Cascade Range
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, ...
with craggy peaks and ridges, deep
glacial valley
U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight s ...
s, and
granite
Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies un ...
spires. Geological events occurring many years ago created the diverse topography and drastic elevation changes over the Cascade Range leading to various climate differences.
The history of the formation of the Cascade Mountains dates back millions of years ago to the late
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...
Epoch. With the
North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Paci ...
overriding the
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate.
The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and I ...
continental lithosphere
A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years or ...
called
terrane
In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its ow ...
s created the
North Cascades
The North Cascades are a section of the Cascade Range of western North America. They span the border between the Canadian province of British Columbia and the U.S. state of Washington and are officially named in the U.S. and Canada as the Casca ...
about 50 million years ago.
During the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured the landscape leaving deposits of rock debris. The "U"-shaped cross section of the river valleys are a result of recent glaciation.
Uplift
Uplift may refer to: Science
* Geologic uplift, a geological process
** Tectonic uplift, a geological process
* Stellar uplift, the theoretical prospect of moving a stellar mass
* Uplift mountains
* Llano Uplift
* Nemaha Uplift
Business
* Upli ...
and faulting in combination with glaciation have been the dominant processes which have created the tall peaks and deep valleys of the North Cascades area.