- Foehn wind
A foehn wind or föhn wind is a type of dry downslope wind which occurs in the lee of a mountain range. It is a rain shadow wind which results from the subsequent
adiabaticwarming of air which has dropped most of its moisture on windward slopes ("see" orographic lift). As a consequence of the different adiabatic lapse rates of moist and dry air, the air on the leeward slopes becomes warmer than equivalent elevations on the windward slopes. Föhn winds can raise temperatures by as much as 30°C (54°F) in just a matter of hours. Central Europeenjoys a warmer climate due to the Föhn.
Winds of this type are called "snow-eaters" for their ability to make
snow melt(also sublimate) rapidly. This snow-removing ability is caused not only by warmer temperatures, but also the low relative humidityof the air mass, having been stripped of moisture by orographic precipitation coming over the mountain(s).
Föhn winds are notorious among
mountaineers in the Alps, especially those climbing the Eiger, for whom the winds add additional difficulty in ascending an already difficult peak.
They are also associated with the rapid spread of
wildfires, making some regions which experience these winds particularly fire-prone.
These winds are often associated with illness ranging from migraines to psychosis. A study by the
Ludwig-Maximilians-Universität Münchenfound that suicide and accidents increased by 10 percent during föhn winds in Central Europe. The causation of Föhnkrankheit(English: Föhn-sickness) is yet unproven. Labelling for preparations of aspirin combined with caffeine, codeine and the like will sometimes include Föhnkrankheit amongst the indications.
The name "föhn" (from the German "Föhn", pronounced IPA| [føːn] ) originated in the alpine region. From Latin "(ventus) favonius", a mild west wind of which Favonius was the Roman personification. ["Concise Oxford Dictionary", 10th edition, Oxford University Press, entry "föhn".]
Regionally, these winds are known by many different names. These include:
Zonda winds in Argentina
Chinook winds in the Rocky Mountains, United States/ Canadaand the Chugach Mountainsof Alaska, United States
*The Nor'wester in
Hawkes Bay, Canterburyand Otago, New Zealand
Wollongongand South Coast, NSW Australia. Often associated with heavy orographic lifitingon the windward side of the escarpment
Halnyin the Carpathian Mountains, Eastern Europe
*Fogony in the Catalan
Bergwindin South Africa
*"Viento del Sur" ("Southern Wind") in the Cantabrian region (northern
Austria, southern Germany, German-speaking regions of Switzerlandand Northern Italy(even non German-speaking regions)
*Favonio in Ticino and Italy
Helm wind, on the Penninesin the Eden Valley, Cumbria, England
In Popular Culture
Peter Camenzind", a novel by Hermann Hesserefers, at length, to the Alpine "Föhn".
* The föhn plays an important part in
Dario Argento's film "Phenomena".
* The Föhn is used for the letter F in "Crazy ABC's" from the album "
Snacktime!" by the Barenaked Ladies.
* The threat of the Föhn drives the protaganists Ayla and Jondalar in
Jean M. Auel's The Plains Of Passage over a glacier before the spring melt. The pair make refereces to the mood altering phenomena of the wind, similar to those of the Santa Ana wind.
AEGregistered the trademark "Fön" in the 1920sfor its hairdryer, which is widely used as a synonymin several languages, such as German, Swiss German, Danish, Italian, Dutch, Norwegian, Czech, Latvian, Romanian, Slovak, Slovenian, Swedish, Turkish and French in western Switzerland.
* McKnight, TL & Hess, Darrel (2000). Foehn/Chinoonk Winds. In , "Physical Geography: A Landscape Appreciation", pp. 132. Upper Saddle River, NJ: Prentice Hall. ISBN 0130202630
* [http://www.bom.gov.au/lam/glossary/fpagegl.shtml#fo Illustration]
* [http://www.flickr.com/photos/snowfactory/2756402718/ Movie of a Foehn situation in the Swiss Alps]
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