s are produced in the Antarctic by katabatic winds Katabatic winds are for example 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, reaching around . 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 oases") 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
sublimates, but is replenished by glacier flow from upstream. In the Fuegian Archipelago (
Tierra del Fuego) in South America as well as in Alaska in North America, a wind known as a
williwaw is a particular danger to harboring vessels. Williwaws originate in the snow and ice fields of the coastal mountains, and they can be faster than . In California, strong katabatic wind events have been responsible for the explosive growth of many wildfires, including the 2018
Camp Fire and the 2020
North Complex. In
Catalonia,
Spain the
Marinada is a fall wind that relieves from the heat inhabitants of the
Urgell region during summer. == See also ==