Spider Mountain is an mountain summit located in the

Glacier Peak Wilderness Glacier Peak Wilderness is a , , wilderness area located within portions of Chelan County, Washington, Chelan, Snohomish County, Washington, Snohomish, and Skagit County, Washington, Skagit counties in the North Cascades of Washington (state), ...

in western Chelan County of

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

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 Provinces and territories of Canada, Canadian province of British Columbia and the U.S. state of Washington (state), Washington and ...

, which is a subset of the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington (state), Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as m ...

Meltwater Meltwater (or melt water) is water released by the melting of snow or ice, including glaciers, glacial ice, tabular icebergs and ice shelf, ice shelves over oceans. Meltwater is often found during early spring (season), spring when snow packs a ...

from the Spider Glacier on the steep north face, and other

surface runoff Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other ...

from the mountain drains into Flat Creek, which is a tributary of the

Stehekin River The Stehekin River is a river located in Washington state in the Pacific Northwest of the United States. It is the main river flowing into Lake Chelan. Miners arrived in Stehekin River Valley in the late 19th century. They were followed by ho ...

Topographic relief Terrain (), alternatively relief or topographical relief, is the dimension and shape of a given surface of land. In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientati ...

is significant as the summit rises above West Fork Flat Creek in one mile (1.6 km). The nearest higher neighbor is Mount Formidable to the west. The Middle Cascade Glacier lies between these two mountains and the Ptarmigan Traverse passes between the two.

Climate

Spider Mountain is located in the

marine west coast An oceanic climate, also known as a marine climate or maritime climate, is the temperate climate sub-type in Köppen classification represented as ''Cfb'', typical of west coasts in higher middle latitudes of continents, generally featuring co ...

climate zone of western North America.Beckey, Fred W. Cascade Alpine Guide, Climbing and High Routes. Seattle, WA: Mountaineers Books, 2008.

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 ins ...

s coming inland from the Pacific Ocean 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 many of those in the ...

. As fronts approach the

, they are forced upward by the peaks (

orographic lift Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it quickly cools down adiabatically, which can raise the relative humidity to 100% and cr ...

), causing them to drop their moisture in the form of rain or snow onto the Cascades. As a result, the North Cascades experience high precipitation, especially during the winter months in the form of snowfall. 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. The months of July through September offer the most favorable weather for climbing or viewing this peak.

Geology

The North Cascades features some of the most rugged topography in the

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 (phanerite, phaneritic) intrusive rock, 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 coo ...

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 ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Epoch. With the North American Plate overriding the Pacific Plate, episodes of volcanic igneous activity persisted. In addition, small fragments of the

oceanic Oceanic may refer to: *Of or relating to the ocean *Of or relating to Oceania **Oceanic climate **Oceanic languages **Oceanic person or people, also called "Pacific Islander(s)" Places * Oceanic, British Columbia, a settlement on Smith Island, ...

and

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 lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time sc ...

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 d ...

s created the

about 50 million years ago. During the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

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 is a result of recent glaciation. Uplift 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.

Gallery

File:Spider Mountain seen from Maple Pass Loop Trail.jpg, Spider Mountain in upper left File:Spider Mountain from SW.jpg, Southwest aspect seen from Green Mountain

References

External links

* Spider Mountain weather
Mountain Forecast
* Spider Mountain photo
Flickr
{{Geographic Location , Center = Spider Mountain , North = Hurry-up Peak , Northeast = Trapper Mountain , East = Flat Creek , Southeast = Rimrock Ridge , South = Sentinel Peak , Southwest =

Le Conte Mountain Le Conte Mountain is a summit located on the shared boundary of Skagit County and Chelan County in Washington state. It is positioned on the crest of the North Cascades Range, and is set within the Glacier Peak Wilderness. Le Conte Mountain ...

, West = Mount Formidable , Northwest = Mix-up Peak Mountains of Chelan County, Washington North Cascades of Washington (state) Two-thousanders of the United States

Climate

Geology

Gallery

See also

References

External links