Jack Mountain

Jack Mountain

Nohokomeen Glacier on the northwest face in 1966
Highest point
Elevation 9,075 ft (2,766 m)  NAVD 88[1]
Prominence 4,211 ft (1,284 m) [2]
Coordinates 48°46′22″N 120°57′22″W / 48.772826164°N 120.956241539°W / 48.772826164; -120.956241539Coordinates: 48°46′22″N 120°57′22″W / 48.772826164°N 120.956241539°W / 48.772826164; -120.956241539 [1]
Geography
Location Whatcom County, Washington, U.S.
Parent range North Cascades
Climbing
First ascent 1904 by E.C. Barnard
Easiest route Climb with exposure, class 4

Jack Mountain is the 17th highest mountain in Washington state.[3] It is one of the 10 non-volcanic peaks in Washington State over 9,000 feet (2,700 m). It towers dramatically over the south end of Ross Lake, rising 7,450 ft (2,271 m) above the lakeshore in only 3 horizontal miles (4.8 km).[4] Nohokomeen Glacier nearly fills the cirque on the upper north slopes of the mountain.

History

Jack Mountain was first described by surveyor Henry Custer in 1859, and was named for prospector Jack Rowley who was active on Canyon Creek.[5] The first recorded ascent of Jack Mountain was made in 1904 by topographer E.C. Barnard.[5] By the 1980s climbing routes had been established on most ridges, glaciers, and directions, seven in total. Most are class 4 but some involve true technical climbing. All are long routes with a great deal of vertical gain,[4] meaning most parties take three to four days to climb the mountain.

Geology

Rock Types

The mountain is composed mostly of Metavolcanic rock and Metasedimentary rock from the Hozameen Group. Most predominate is Greenstone from the Jurassic to Permian periods. Most surface material is heavily eroded, by water Glacier ice. The lower flanks of the mountain in the Devils creek basin Maine sedimentary rock from the lower Cretaceous period, part of the Harts Pass Formation. The lower flanks of the mountain on the Ross lake side are composed of many diffent rock types including Orthogneiss, Ultramafic rock, low grade Phyllite, Tonalite, Continental glacier drift, Diorite, and Schist.

Faults and Formation

The Jack Mountain area consists of one small thrust fault, and a few other normal faults, none showing any seismic activity. Jack Mountain was created when the Hozameen Group was thrusted over the younger Harts Pass formation to the east. Most likely caused by the Ross lake Fault to the west. The lower flanks of the mountain to the west were created by the Ruby Creek Heterogeneous plutonic belt.[6][7]

Geographical features

Routes

References

  1. 1 2 "Jack". NGS data sheet. U.S. National Geodetic Survey.
  2. ↑ "Jack Mountain, Washington". Peakbagger.com.
  3. ↑ Howbert, Jeff. "Washington 100 Highest Peaks". The Northwest Peakbaggers Asylum.
  4. 1 2 Beckey, Fred W. (1995). Cascade alpine guide : climbing and high routes. Vol. 2, Stevens Pass to Rainy Pass (2nd ed.). Mountaineers Books. pp. 196–199. ISBN 978-0-89886-423-6.
  5. 1 2 Majors, Harry M. (1975). Exploring Washington. Van Winkle Publishing Co. p. 29. ISBN 978-0-918664-00-6.
  6. ↑ https://fortress.wa.gov/dnr/geology/?Theme=wigm, Surface geology map layer.
  7. 1 2 Beckey, Fred W. Cascade Alpine Guide, Climbing and High Routes Pg 202, 203, 204, 205. Seattle, WA: Mountaineers Books, 2008.

External links


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