Split Thumb is a glaciated mountain summit located in the

Boundary Ranges The Boundary Ranges, also known in the singular and as the Alaska Boundary Range, are the largest and most northerly subrange of the Coast Mountains. They begin at the Nass River, near the southern end of the Alaska Panhandle in the Canadian pro ...

of the

Coast Mountains The Coast Mountains () are a major mountain range in the Pacific Coast Ranges of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the British Columbia Coast, Coast of British Columbia sout ...

, in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

. The peak is situated near the southern periphery of the

Juneau Icefield The Juneau Icefield is an ice field located just north of Juneau, Alaska, Juneau, Alaska, continuing north through the border with British Columbia, extending through an area of in the Coast Mountains, Coast Range ranging north to south and east ...

, northeast of

Juneau Juneau ( ; ), officially the City and Borough of Juneau, is the capital of the U.S. state of Alaska, located along the Gastineau Channel and the Alaskan panhandle. Juneau was named the capital of Alaska in 1906, when the government of wha ...

, 2.15 mi (3 km) southeast of Nugget Mountain, and east of Heintzleman Ridge, on land managed by

Tongass National Forest The Tongass National Forest () in Southeast Alaska is the largest U.S. National Forest at , an expanse larger than 10 U.S. states and 75 U.N. member nations. Most of its area is temperate rain forest and is remote enough to be home to many s ...

. Split Thumb is surrounded by the Lemon Creek Glacier to the west, and Norris Glacier to east. The Split Thumb

Icefall An icefall is a portion of certain glaciers characterized by relatively rapid flow and chaotic crevassed surface, caused in part by gravity. The term ''icefall'' is formed by analogy with the word ''waterfall'', which is a similar phenomenon of ...

is set on the east aspect of the peak. This peak's descriptive name was published in 1951 by the

U.S. Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March ...

. The

first ascent In mountaineering and climbing, a first ascent (abbreviated to FA in climbing guidebook, guide books), is the first successful documented climb to the top of a mountain or the top of a particular climbing route. Early 20th-century mountaineers a ...

of Split Thumb was made July 2, 1954, by a Juneau Icefield Research Project party comprising

Edward LaChapelle Edward Randle "Ed" LaChapelle (May 31, 1926 – February 1, 2007) was an American avalanche researcher, glaciologist, mountaineer, skier, author, and professor. He was a pioneer in the field of avalanche research and forecasting in North America. ...

, Dick Hubley, Carlton Ray, Dr. Conrad Buettner, and Bob Goodwin.

Climate

Based on the

Köppen climate classification The Köppen climate classification divides Earth climates into five main climate groups, with each group being divided based on patterns of seasonal precipitation and temperature. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (te ...

, Split Thumb is located in a

subarctic climate The subarctic climate (also called subpolar climate, or boreal climate) is a continental climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of ...

zone, with long, cold, snowy winters, and cool summers. Weather systems coming off the

Gulf of Alaska The Gulf of Alaska ( Tlingit: ''Yéil T'ooch’'') is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the ...

are forced upwards by the Coast Mountains (

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 heavy precipitation in the form of rainfall and snowfall. Winter temperatures can drop below 0 °F with wind chill factors below −10 °F. The month of July offers the most favorable weather to view or climb Split Thumb.

Gallery

File:Split Thumb (pano).jpg, Looking north at Split Thumb as seen from Observation Peak File:Split Thumb - Alaska.jpg, North aspect File:South aspect of Split Thumb.jpg, South aspect File:Split Thumb at the Juneau Icefield.jpg, Northeast aspect

Climate

Gallery

See also

References

External links