(Yakut), flat, basin-type settlement depressions found in permafrost regions. These depressions were formed by warming of the climate accompanied by thawing of subsurface ice. Diameters of the depressions vary from tens of meters up to several kilometers; depths range from 1 to 15 m (more rarely up to 30 m). The depressions are covered with meadow and steppe vegetation; residual lakes are characteristic. Alasy are typical of the Yakut plains, which are subject to thermal karst formation. Land in the alasy is used for agricultural purposes.
Dried oxbow lakes, solution sinks, and other relief forms are sometimes called alasy.