Katabatic Wind - Impacts

Impacts

Katabatic winds are most commonly found blowing out from the large and elevated ice sheets of Antarctica and Greenland. The buildup of high density cold air over the ice sheets and the elevation of the ice sheets brings into play enormous gravitational energy. Where these winds are concentrated into restricted areas in the coastal valleys, the winds blow well over hurricane force. In Greenland these winds are called Piteraq and are most intense whenever a low pressure area approaches the coast.

In a few regions of continental Antarctica the snow is scoured away by the force of the katabatic winds, leading to "dry valleys" (or "Antarctic oasis") such as the McMurdo Dry Valleys. Since the katabatic winds are descending, they tend to have a low relative humidity which desiccates the region. Other regions may have a similar but lesser effect, leading to "blue ice" areas where the snow is removed and the surface ice evaporates, but is replenished by glacier flow from upstream.

In the Fuegian Archipelago (or Tierra del Fuego) in South America as well as in Alaska, a wind known as a williwaw is a particular danger to harbouring vessels. Williwaws originate in the snow and ice fields of the coastal mountains, and while they commonly blow as high as 100 knots, 200-knot williwaws have been reported.