Amphitheater Mountain (Washington)

Amphitheater Mountain[3] is an 8,358-foot (2,548-metre) multi-peak mountain located in Okanogan County in Washington state. It is part of the Okanogan Range which is a sub-range of the North Cascades and Cascade Range. The mountain is situated on the east side of the Cascade crest, in the Pasayten Wilderness, on land administered by Okanogan National Forest. The sprawling Amphitheater Mountain has several sub-peaks including the South Peak (8269 ft/2520 m), West Peak (8252 ft/2515 m), and North Peak (8200 ft/2499 m).[1] The nearest higher peak is Cathedral Peak, 0.95 miles (1.53 km) to the north.[1] The Pacific Northwest Trail traverses below the north slope of Amphitheater Mountain as it crosses Cathedral Pass. Precipitation runoff from Amphitheater Mountain drains west into Cathedral Fork, or east into Cathedral Creek.

Amphitheater Mountain
Amphitheater Mountain from Upper Cathedral Lake at sunset.
Highest point
Elevation8,358 ft (2,548 m) [1]
Prominence758 ft (231 m) [1]
Coordinates48°58′32″N 120°11′32″W [1]
Geography
Amphitheater Mountain
Location of Amphitheater Mountain in Washington
Amphitheater Mountain
Amphitheater Mountain (the United States)
Location
Parent rangeOkanogan Range
North Cascades
Cascade Range
Topo mapUSGS Remmel Mountain
Geology
Type of rockGranite
Climbing
First ascent1901 by Calkins, Smith[2]
Easiest routeScrambling class 3

Climate

Most weather fronts originate in the Pacific Ocean, and travel northeast toward the Cascade Mountains. As fronts approach the North Cascades, they are forced upward by the peaks of the Cascade Range, causing them to drop their moisture in the form of rain or snowfall onto the Cascades (Orographic lift). As a result, the west side of the North Cascades experiences higher precipitation than the east side, 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.[4]

Geology

The North Cascades features some of the most rugged topography in the Cascade Range with craggy peaks, spires, ridges, and deep glacial valleys. Geological events occurring many years ago created the diverse topography and drastic elevation changes over the Cascade Range leading to the various climate differences.

Amphitheater Mountain from Cathedral Pass

The history of the formation of the Cascade Mountains dates back millions of years ago to the late Eocene Epoch.[5] With the North American Plate overriding the Pacific Plate, episodes of volcanic igneous activity persisted.[5] In addition, small fragments of the oceanic and continental lithosphere called terranes created the North Cascades about 50 million years ago.[5]

During the Pleistocene period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured the landscape leaving deposits of rock debris.[5] The "U"-shaped cross section of the river valleys are 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.

Climbing Routes

Established rock climbing routes on Amphitheater Mountain:[6]

See also

References
  1. "Amphitheater Mountain, Washington". Peakbagger.com.
  2. "Amphitheater Mountain". Bivouac.com. Retrieved 2019-06-22.
  3. "Amphitheater Mountain". Geographic Names Information System. United States Geological Survey. Retrieved 2019-06-21.
  4. Beckey, Fred W. Cascade Alpine Guide, Climbing and High Routes. Seattle, WA: Mountaineers Books, 2008.
  5. Kruckeberg, Arthur (1991). The Natural History of Puget Sound Country. University of Washington Press.
  6. Amphitheatre Mountain Rock Climbing Mountain Project
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