Four Brothers is a mountain

summit A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. The topography, topographic terms acme, apex, peak (mountain peak), and zenith are synonymous. The term (mountain top) is generally used ...

located in

Kittitas County Kittitas County () is a county located in the U.S. state of Washington. At the 2020 census, its population was 44,337. Its county seat and largest city is Ellensburg. The county was created in November 1883 when it was carved out of Yakima Coun ...

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 on ...

state.

Description

Four Brothers is set within the

Alpine Lakes Wilderness The Alpine Lakes Wilderness is a large National Wilderness Preservation System, wilderness area spanning the Central Cascades of Washington (state), Washington state in the United States. The wilderness is located in parts of Wenatchee National F ...

on land managed by Wenatchee National Forest. Four Brothers is northeast of

Snoqualmie Pass Snoqualmie Pass is a mountain pass that carries Interstate 90 (I-90) through the Cascade Range in the U.S. state of Washington. The pass summit is at an elevation of , on the county line between Kittitas County and King County. Snoqualmie Pass ...

, on Chikamin Ridge, southeast of its parent,

Chikamin Peak Chikamin Peak is a mountain summit located in the Cascade Range, in Kittitas County, Washington, Kittitas County of Washington (U.S. state), Washington state. It is situated within the Alpine Lakes Wilderness on land managed by the Okanogan–W ...

. The Pacific Crest Trail traverses the west slope of Four Brothers, and again on the east side as it crosses the gap between Four Brothers and Three Queens. The mountain is part 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 and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

and is within the

Yakima River The Yakima River is a tributary of the Columbia River in south central and eastern Washington state, named for the indigenous Yakama people. Lewis and Clark mention in their journals that the Chin-nâm pam (or the Lower Snake River Chamnapam Nat ...

drainage basin. Precipitation runoff from the mountain drains west into headwaters of Gold Creek, or east into Glacier Lake. The mountain was named in the 1890s for brothers John, Tom, Vic, and Lawrie Denny, miners who lived in a cabin at the base of the four peaks.

Climate

Four Brothers is located in the marine west coast 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 the Car ...

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

, and travel northeast toward the Cascade Mountains. As fronts approach, 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 ...

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 ( Orographic lift). 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.

Geology

The Alpine Lakes Wilderness 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 (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 undergro ...

walls spotted with over 700 mountain lakes. Geological events occurring many years ago created the diverse topography and drastic elevation changes over the Cascade Range leading to the various climate differences. These climate differences lead to vegetation variety defining the

ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of l ...

s in this area. The elevation range of this area is between about in the lower elevations to over on

Mount Stuart Mount Stuart is a mountain in the Cascade Range, in the U.S. state of Washington. It is the second highest non-volcanic peak in the state, after Bonanza Peak and seventh-highest overall. Mount Stuart is the highest peak in the Stuart Range, and ...

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

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 Pacific ...

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 Iza ...

, 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 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 own ...

s created the North Cascades 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 last glacial retreat in the Alpine Lakes area began about 14,000 years ago and was north of the Canada–US border by 10,000 years ago. The U-shaped cross section of the river valleys is a result of that 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 * Uplif ...

and faulting in combination with glaciation have been the dominant processes which have created the tall peaks and deep valleys of the Alpine Lakes Wilderness area.

Gallery

File:Four Brothers along Chikamin Ridge.jpg, East aspect File:Chikamin and Four Brothers.jpg, Chikamin Peak and Four Brothers (right) in winter File:Four Brothers, Washington.jpg, Four Brothers

References

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External links