Alas () is a shallow depression which occurs primarily in
Yakutia
Sakha, officially the Republic of Sakha (Yakutia), is a republics of Russia, republic of Russia, and the largest federal subject of Russia by area. It is located in the Russian Far East, along the Arctic Ocean, with a population of one million ...
, which is formed by subsidence of the
Arctic
The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
permafrost
Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below ...
owing to repeated melting and refreezing. An alas first develops as a shallow lake as melt water fills the depression. The lake eventually dries out and is replaced by grasses and other
herbaceous
Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials.
Definitions of "herb" and "herbaceous"
The fourth edition of ...
vegetation.
Examples
An alas is different from
thermokarst
Thermokarst is a type of terrain characterised by very irregular surfaces of marshy hollows and small hummocks formed when ice-rich permafrost thaws. The land surface type occurs in Arctic areas, and on a smaller scale in mountainous areas such ...
depressions found elsewhere in the Arctic in that the lake is only temporary. Due to the aridity of Yakutia, the lake will dry up once the underlying ice has been depleted.
Alases are often used for pasturage for horses as well as hay-fields. They are common in the
Central Yakutian Lowland. The largest alas in the world is
Myuryu, located in
Ust-Aldan District.
Evolution of the Alas of Central Yakutia
(in Russian)
The alas also hold great cultural importance. During the festival of Ysyakh, the traditional Yakut New Year’s day celebrated in the summer, as many as 20,000 gather to an alas in the general vicinity of Yakutsk
Yakutsk ( ) is the capital and largest city of Sakha, Russia, located about south of the Arctic Circle. Fueled by the mining industry, Yakutsk has become one of Russia's most rapidly growing regional cities, with a population of 355,443 at the ...
. Other minor celebrations occur at other alas across the Republic of Sakha. Once set up there, temporary Uraha ( Yakut: Ураһа), which are homes made of birch bark are constructed among other wooden idols and structures.
See also
* Baydzharakh
* Yedoma
Yedoma () is an organic-rich (about 2% carbon by mass) Pleistocene-age permafrost with ice content of 50–90% by volume. Yedoma are abundant in the cold regions of eastern Siberia, such as northern Sakha Republic, Yakutia, as well as in Alaska ...
References
*
External links
*
Geography of Russia
Permafrost
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