Jumbo Peak is a volcanic mountain summit located in the

Gifford Pinchot National Forest Gifford Pinchot National Forest is a National Forest located in southern Washington, managed by the United States Forest Service. With an area of 1.32 million acres (5300 km2), it extends 116 km along the western slopes of Cascade Ran ...

, in

Skamania County Skamania County () is a county located in the U.S. state of Washington. As of the 2020 census, the population was 12,036. The county seat and largest incorporated city is Stevenson, although the Carson River Valley CDP is more populous. The ...

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 situated in the Cascade Range, northwest of Mount Adams, east-northeast of

Mount St. Helens Mount St. Helens (known as Lawetlat'la to the indigenous Cowlitz people, and Loowit or Louwala-Clough to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United St ...

, and south of Mount Rainier. Its nearest higher neighbor is Sunrise Peak, to the north-northeast. Precipitation

runoff Runoff, run-off or RUNOFF may refer to: * RUNOFF, the first computer text-formatting program * Runoff or run-off, another name for bleed, printing that lies beyond the edges to which a printed sheet is trimmed * Runoff or run-off, a stock marke ...

from Jumbo Peak drains into tributaries of the

Cowlitz River The Cowlitz River is a river in the state of Washington in the United States, a tributary of the Columbia River. Its tributaries drain a large region including the slopes of Mount Rainier, Mount Adams, and Mount St. Helens. The Cowlitz has a d ...

drainage basin. The Juniper Ridge Trail (#261) which skirts this peak provides access to this remote peak.

Geology

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 Pacif ...

overriding the Pacific Plate, episodes of volcanic igneous activity occurred. Mount Adams, a stratovolcano that is southeast of Jumbo Peak, began forming in the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological 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 finally confirmed in ...

.Beckey, Fred W. Cascade Alpine Guide, Climbing and High Routes. Seattle, WA: Mountaineers Books, 2008. Due to Mount St. Helens' proximity to Jumbo Peak,

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer ...

is common in the area. Jumbo Peak is composed of

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomin ...

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

that intruded up into older volcanic rocks more than five million years ago and is now surrounded by a forest of old-growth Douglas fir and

mountain hemlock ''Tsuga mertensiana'', known as mountain hemlock, is a species of hemlock native to the west coast of North America, found between Southcentral Alaska and south-central California. Description ''Tsuga mertensiana'' is a large evergreen conifer ...

Climate

Jumbo 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.Beckey, Fred W. Cascade Alpine Guide, Climbing and High Routes. Seattle, WA: Mountaineers Books, 2008. Most

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 contin ...

, 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, they are forced upward by the peaks of the Cascade Range (

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 snowfall onto the Cascades. As a result, the west side of the Cascades experiences 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.

References

External links

{{Commons, Jumbo Peak, Jumbo Peak * Weather forecast
Jumbo Peak
* National Forest Service
Gifford Pinchot National Forest
* Hiking Jumbo Peak
Washington Trails Association
Cascade Range Mountains of Skamania County, Washington Mountains of Washington (state) North American 1000 m summits Volcanoes of Washington (state) Lava domes Cascade Volcanoes

Geology

Climate

See also

References

External links