Ahklun Mountains
Encyclopedia
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
and support the only existing glacier
s in western Alaska. 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.
The Ahklun Mountains, with its many deep lakes (some over 400 meters in depth), covers approximate 80 percent of the Togiak National Wildlife Refuge before sloping to tundra
and then coastal plains.
, 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. Blackpoll warbler
s 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.. The average annual precipitation ranges from 19 to 25 in (482.6 to 635 mm), while the average annual temperature ranges from 29 to 33 °F (-1.7 to 0.555555555559977 C). The growing season extends approximately from May 15 to September 10.
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.
Geological evidence show that during the Pleistocene
era there were repeated glaciations that have carved out a large number of valley trough
s. On the eastern side, these troughs contain networks of glacial lake
s, some that are over 400 m deep, and dammed by glacier terminus
moraine
s. On the southern and western side, the valleys are broader and are interspersed with rolling upland
s pierced by rugged massif
s.
Togiak National Wildlife Refuge
Dominated by the Ahklun Mountains in the north and the cold waters of Bristol Bay to the south, Togiak National Wildlife Refuge confronts the traveler with a kaleidoscope of landscapes. The natural forces that have shaped this land range from the violent and powerful to the geologically patient...
in southwest Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
. They extend southwest from the Kanektok
Kanektok River
The Kanektok River is a river in Alaska. It is located in the Togiak National Wildlife Refuge and flows westward from Pegati Lake and into the Bering Sea at the city of Quinhagak.-See also:*List of Alaska rivers*Togiak Wilderness...
and Narogurum Rivers to Hagemeister Strait and Kuskokwim Bay
Kuskokwim Bay
Kuskokwim Bay is a bay in southwestern Alaska, at about . It is about long, and wide.The Kuskokwim River empties into Kuskokwim Bay. The bay got its name from the river. The largest community on the bay is the city of Quinhagak....
and support the only existing glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
s in western Alaska. They are the highest Alaskan mountain range west of the Alaska Range
Alaska Range
The Alaska Range is a relatively narrow, 650-km-long mountain range in the southcentral region of the U.S. state of Alaska, from Lake Clark at its southwest end to the White River in Canada's Yukon Territory in the southeast...
and north of the Alaska Peninsula
Alaska Peninsula
The Alaska Peninsula is a peninsula extending about to the southwest from the mainland of Alaska and ending in the Aleutian Islands. The peninsula separates the Pacific Ocean from Bristol Bay, an arm of the Bering Sea....
, with some summits over 1500 m high, and home to numerous glaciers. To the west is the Kuskokwim River
Kuskokwim River
The Kuskokwim River or Kusko River is a river, long, in Southwest Alaska in the United States. It is the ninth largest river in the United States by average discharge volume at its mouth and seventeenth largest by basin drainage area.The river provides the principal drainage for an area of the...
and to the east is the Bristol Bay
Bristol Bay
Bristol Bay is the eastern-most arm of the Bering Sea, at 57° to 59° North 157° to 162° West in Southwest Alaska. Bristol Bay is 400 km long and 290 km, wide at its mouth...
lowlands.
The Ahklun Mountains, with its many deep lakes (some over 400 meters in depth), covers approximate 80 percent of the Togiak National Wildlife Refuge before sloping to tundra
Tundra
In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...
and then coastal plains.
Environment
The Ahklun Mountains are dominated by alpine tundraAlpine tundra
Alpine tundra is a natural region that does not contain trees because it is at high altitude. Alpine tundra is distinguished from arctic tundra, because alpine soils are generally better drained than arctic soils...
, heath
Heath (habitat)
A heath or heathland is a dwarf-shrub habitat found on mainly low quality acidic soils, characterised by open, low growing woody vegetation, often dominated by plants of the Ericaceae. There are some clear differences between heath and moorland...
, and barrens, while moist sedge
Sedge
- Plants :* Acorus calamus, sweet flag, a plant in the Acoraceae family* Any of the plants in the family Cyperaceae- Animals :* A collective noun for several species of birds, including bitterns, cranes and herons* Sedge-fly, caddisfly- Other uses :...
-tussock
Tussock
Tussock most often refers to a small hillock of grassy, or grass-like plant growth, but may also refer to Plants and ecology, Insects.- Plants and ecology :*Tussock *New Zealand tussock grasslands*Serrated Tussock...
meadows occur in valley bottoms. Black spruce
Black Spruce
Picea mariana is a species of spruce native to northern North America, from Newfoundland west to Alaska, and south to northern New York, Minnesota and central British Columbia...
forest occurs on some hills and ridges. Forests of white spruce
White Spruce
Picea glauca is a species of spruce native to boreal forests in the north of North America, from central Alaska east to Newfoundland, and south to northern Montana, Minnesota, Wisconsin, Michigan, upstate New York, Vermont, New Hampshire, and Maine; there is also an isolated population in the...
, paper birch
Paper Birch
Betula papyrifera is a species of birch native to northern North America.-Description:...
, and alder
Alder
Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...
cover the low hills along the major rivers. Blackpoll warbler
Blackpoll Warbler
The Blackpoll Warbler, Dendroica striata , is a New World warbler. Breeding males are mostly black and white. They have a prominent black cap, white cheeks and white wing bars. The Blackpoll breeds in northern North America, from Alaska, through most of Canada, and into the Great Lakes region and...
s are common breeders in conifer stands in river valleys. Beaver
Beaver
The beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, North American Beaver and Eurasian Beaver . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...
are abundant, supporting a large annual harvest. Sockeye salmon
Sockeye salmon
Sockeye salmon , also called red salmon or blueback salmon in the USA, is an anadromous species of salmon found in the Northern Pacific Ocean and rivers discharging into it...
are the most abundant fish. Chum
Chum salmon
The chum salmon, Oncorhynchus keta, is a species of anadromous fish in the salmon family. It is a Pacific salmon, and may also be known as dog salmon or Keta salmon, and is often marketed under the name Silverbrite salmon...
, king, silver salmon, and rainbow trout
Rainbow trout
The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....
are also numerous.. The average annual precipitation ranges from 19 to 25 in (482.6 to 635 mm), while the average annual temperature ranges from 29 to 33 °F (-1.7 to 0.555555555559977 C). The growing season extends approximately from May 15 to September 10.
Glaciers
Photogrammetry
Photogrammetry is the practice of determining the geometric properties of objects from photographic images. Photogrammetry is as old as modern photography and can be dated to the mid-nineteenth century....
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.
Geological evidence show that during the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
era there were repeated glaciations that have carved out a large number of valley trough
Trough (geology)
In geology, a trough generally refers to a linear structural depression that extends laterally over a distance, while being less steep than a trench.A trough can be a narrow basin or a geologic rift....
s. On the eastern side, these troughs contain networks of glacial lake
Glacial lake
A glacial lake is a lake with origins in a melted glacier. Near the end of the last glacial period, roughly 10,000 years ago, glaciers began to retreat. A retreating glacier often left behind large deposits of ice in hollows between drumlins or hills. As the ice age ended, these melted to create...
s, some that are over 400 m deep, and dammed by glacier terminus
Glacier terminus
A glacier terminus, or snout, is the end of a glacier at any given point in time. Although glaciers seem motionless to the observer, in reality glaciers are in endless motion and the glacier terminus is always either advancing or retreating...
moraine
Moraine
A moraine is any glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past glacial maximum. This debris may have been plucked off a valley floor as a glacier advanced or it may have...
s. On the southern and western side, the valleys are broader and are interspersed with rolling upland
Highland (geography)
The term highland or upland is used to denote any mountainous region or elevated mountainous plateau. Generally speaking, the term upland tends to be used for ranges of hills, typically up to 500-600m, and highland for ranges of low mountains.The Scottish Highlands refers to the mountainous...
s pierced by rugged massif
Massif
In geology, a massif is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole...
s.