Ahklun Mountains
| Ahklun Mountains | |
|---|---|
 View of the Ahklun Mountains reflected in a mirror-smooth glacial lake |
|
| Dimensions | |
| Length | 80 mi (130 km) |
| Width | 30 mi (48 km) |
| Geography | |
| Country | United States |
| State | Alaska |
| Range coordinates | 59°23′00″N 160°42′00″W / 59.3833°N 160.7°WCoordinates: 59°23′00″N 160°42′00″W / 59.3833°N 160.7°W |
The Ahklun Mountains are located in the northeast section of the Togiak National Wildlife Refuge in southwest Alaska. They extend southwest from the Kanektok and Narogurum Rivers to Hagemeister Strait and Kuskokwim Bay[1] and support the only existing glaciers in western Alaska.[2] They are the highest Alaskan mountain range west of the Alaska Range and north of the Alaska Peninsula, with some summits over 1500 m high, and home to numerous glaciers. To the west is the Kuskokwim River and to the east is the Bristol Bay lowlands.[3]
The Ahklun Mountains, with its many deep lakes (some over 400 meters in depth[3]), covers approximate 80 percent of the Togiak National Wildlife Refuge before sloping to tundra and then coastal plains.[4]
Contents |
Environment[edit]
The Ahklun Mountains are dominated by alpine tundra, heath, and barrens, while moist sedge-tussock meadows occur in valley bottoms. Black spruce forest occurs on some hills and ridges. Forests of white spruce, paper birch, and alder cover the low hills along the major rivers.[5] Blackpoll warblers are common breeders in conifer stands in river valleys. Beaver are abundant, supporting a large annual harvest. Sockeye salmon are the most abundant fish. Chum, king, silver salmon, and rainbow trout are also numerous.[5] The average annual precipitation ranges from 19 to 25 inches (480 to 640 mm), while the average annual temperature ranges from 29 to 33 °F (-2 to 1 °C). The growing season extends approximately from May 15 to September 10.[5]
Glaciers[edit]
The glaciers were first mapped by the U.S. Geological Survey, who used photogrammetry methods based on a 1972 series of aerial photos, revealing the presence of 116 glaciers. In 2006, of the original 109 that were resurveyed, the existence of 97 were verified and 12 were assessed having disappeared. This is a reduction of 11 percent. Of the remaining glaciers, many were much smaller than their size in 1972. This finding indicates that there has been a large decrease in the amount of land area covered by glacial ice in these mountains. The scientific community has long recognized the importance of glaciers as indicators of climatic change.[2]
Geological evidence show that during the Pleistocene era there were repeated glaciations that have carved out a large number of valley troughs. On the eastern side, these troughs contain networks of glacial lakes, some that are over 400 m deep, and dammed by glacier terminus moraines.[3] On the southern and western side, the valleys are broader and are interspersed with rolling uplands pierced by rugged massifs.[3]
Lowlands[edit]
In the lowlands, areas not reached by the glaciation, the principal geographic features are the moraines and ridges formed by thrusting ice.[3]
Notes[edit]
- ^ "Ahklun Mountains". Geographic Names Information System, U.S. Geological Survey.
- ^ a b Walsh et al, Patrick. "Inventory of the Ahklun Mountain glaciers, southwest Alaska". nalaska.fws.gov. Retrieved 2009-10-18.
- ^ a b c d e "AMP: The Ahklun Mountains Region". www4.nau.edu. Retrieved 2009-10-18.
- ^ "Wilderness.net - Togiak Wilderness". www.wilderness.net. Retrieved 2009-10-19.
- ^ a b c
This article incorporates public domain material from the United States Department of Agriculture document "Ahklun Mountains Tundra - Meadow (Ecoregions of the United States)" (retrieved on 2009-10-25).
This article incorporates External links[edit]
- "The Ahklun Mountains Project Web Site". www4.nau.edu. Retrieved 2009-10-18.
- Briner, Jason P.; Kaufman, Darrell S. "Late Pleistocene Glaciation of the Southwestern Ahklun Mountains, Alaska". Quaternary Research. doi:10.1006/qres.1999.2088. Retrieved 2009-10-19.
- Briner, Jason; et al. "Glacier readvance during the late glacial (Younger Dryas?) in the Ahklun Mountains, southwestern Alaska". Geology (GSA) 30 (8): 679. doi:10.1130/0091-7613(2002)030<0679:GRDTLG>2.0.CO;2. Retrieved 2009-10-19.
- "Chapter 6-Ahklun Mountains Tundra--Meadow Province". United States Forest Service. Archived from the original on 25 October 2009. Retrieved 2009-10-19.
