Plummer Mountain is a prominent summit 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 ...

, in

Snohomish County Snohomish County () is a county located in the U.S. state of Washington. With a population of 827,957 as of the 2020 census, it is the third-most populous county in Washington, after nearby King and Pierce counties, and the 72nd-most popul ...

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 located west of Suiattle Pass in the heart of 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), ...

on land managed by

Mount Baker-Snoqualmie National Forest Mount is often used as part of the name of specific mountains, e.g. Mount Everest. Mount or Mounts may also refer to: Places * Mount, Cornwall, a village in Warleggan parish, England * Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, ...

. Plummer Mountain is the high point and eastern culmination of Miners Ridge. Image Lake on Miners Ridge provides a campsite from which to climb Plummer.

Kennecott Copper Corporation Kennicott or Kennecott may refer to: * Kennecott, Alaska Kennecott, also known as Kennicott and Kennecott Mines, is an abandoned mining camp in the Copper River Census Area in the U.S. state of Alaska that was the center of activity for seve ...

, as of 1988, planned to dig an open-pit copper mine on the slopes of Plummer Mountain. However, protests by various advocacy groups prevented the plan from developing further.''The Open Pit Is Finally Put Away'', Seattle PI, May 5, 2010

Geology

Subduction and tectonic activity in the area began during the

late cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

, about . The area was previously an oceanic environment, consisting mainly of

sedimentary Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedime ...

and

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

rocks.Beckey, Fred W. Cascade Alpine Guide, Climbing and High Routes. Seattle, WA: Mountaineers Books, 2008. Extensive volcanic activity began to take place in the

oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

, about . However,

mountain building Mountain formation occurs due to a variety of geological processes associated with large-scale movements of the Earth's crust (List of tectonic plates, tectonic plates). Fold (geology), Folding, Fault (geology), faulting, Volcano, volcanic acti ...

in the area did not begin until the

miocene 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 ...

, approximately . Plummer Mountain is located in the Cloudy Pass

batholith A batholith () is a large mass of intrusive rock, intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate ...

, an intrusive formation that was formed approximately , during the early miocene.

Glacier Peak Glacier Peak or Dakobed (known in the Sauk-Suiattle dialect of the Lushootseed language as "Tda-ko-buh-ba" or "Takobia") is the most isolated of the five major stratovolcanoes (composite volcanoes) of the Cascade Volcanoes, Cascade Volcanic Arc ...

, a

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

that is south of Plummer Mountain, began forming in the mid-

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 ...

. Due to Glacier Peak's proximity to Plummer Mountain,

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

is quite common in the area. Throughout the

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

, the North Cascades were mostly covered in thick glaciers, extending to near

Puget Sound Puget Sound ( ; ) is a complex estuary, estuarine system of interconnected Marine habitat, marine waterways and basins located on the northwest coast of the U.S. state of Washington (state), Washington. As a part of the Salish Sea, the sound ...

. Glaciation was most prevalent approximately , and most valleys were ice-free by . As a result, valleys in the area are deep and

U-shaped Many shapes have metaphorical names, i.e., their names are metaphors: these shape A shape is a graphics, graphical representation of an object's form or its external boundary, outline, or external Surface (mathematics), surface. It is distinc ...

, and mountains tend to be rocky, with steep slopes and narrow summits.

Climate

Plummer 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. 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 ins ...

s originating in 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 North Cascades, 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 North Cascades experiences high precipitation, especially during the winter months in the form of snowfall. 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 Grade (slope), slope, such as a hill or mountain. Avalanches can be triggered spontaneously, by factors such as increased precipitation or snowpack weakening, or by external means such as humans, othe ...

danger. 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. Due to its temperate climate and proximity to the Pacific Ocean, areas west of the Cascade Crest very rarely experience temperatures below or above .

Hiking

The trail to Miners Ridge can be accessed from the

Suiattle River The Suiattle River ( ) is a river in the northern Cascade Mountains of western Washington (state), Washington, United States. It is a tributary of the Sauk River (Washington), Sauk River and by extension the Skagit River. Its source is located ...

Road. There is an alpine route with

scrambling Scrambling is a mountaineering term for ascending steep terrain using one's hands to assist in holds and balance.''New Oxford American Dictionary''. It can be described as being between hiking and climbing, rock climbing. "A scramble" is a relat ...

that leads from Miners Ridge to Plummer Mountain.

Gallery

File:Plummer Mountain snowy.jpg, Plummer seen from Cloudy Pass File:Plummer Mountain from Suiattle Pass.jpg, East aspect seen from Suiattle Pass File:Miners Ridge in the Glacier Peak Wilderness.jpg, Miners Ridge below Plummer Mountain File:Plummer Mountain and Bonanza.jpg, West aspect of Plummer Mountain (center) with Bonanza Peak (behind, left) File:West aspect of Plummer.jpg, West aspect

References

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External links