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How Foehn is produced

Foehn clouds in Geneva (Switzerland)

A foehn wind or föhn wind is a type of dry down-slope wind which occurs in the lee of a mountain range. It is a rain shadow wind which results from the subsequent adiabatic warming 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 Europe enjoys a warmer climate due to the Föhn.

Effects

Winds of this type are called "snow-eaters" for their ability to make snow melt or sublimate rapidly. This snow-removing ability is caused not only by warmer temperatures, but also the low relative humidity of 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 further 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 illnesses ranging from migraines to psychosis.The first clinical review of these effects was published by the Austrian physician, Anton Czermak in the Nineteenth Century. ^[1] A study by the Ludwig-Maximilians-Universität München found that suicide and accidents increased by 10 percent during föhn winds in Central Europe. The causation of Föhnkrankheit (English: Föhn-sickness) is yet unproven. Labeling for preparations of aspirin combined with caffeine, codeine and the like will sometimes include Föhnkrankheit amongst the indications.

Etymology

The name föhn (German: Föhn, pronounced [ˈføːn]) originated in the alpine region. From Latin (ventus) favonius, a mild west wind of which Favonius was the Roman personification.^[2]

Local examples

Regionally, these winds are known by many different names. These include:

• Lyvas wind in Elefsina, Athens in Greece
• Zonda winds in Argentina
• Chinook winds east of the Rocky Mountains, in the United States and Canada, and east of the Chugach Mountains of Alaska, United States
• The Nor'wester in Hawkes Bay, Canterbury and Otago, New Zealand
• Föhn in Wollongong and South Coast, NSW Australia. Often associated with heavy orographic lifiting on the windward side of the escarpment
• Halny in the Carpathian Mountains, Eastern Europe
• Fogony in the Catalan Pyrenees
• Bergwind in South Africa
• Viento del Sur (Southern Wind) in the Cantabrian region (northern Spain)
• Terral in Málaga (southern Spain)
• Föhn in Austria, southern Germany, German-speaking regions of Switzerland and Northern Italy (even non German-speaking regions)
• Puelche wind in Chile.
• Favonio in Ticino and Italy
• The Helm wind, on the Pennines in the Eden Valley, Cumbria, England
• Garmoosh, Garmesh, Garmbaad (Warm Wind): (Persian: گرمباد, Gilaki: گرموش) in Gilan region, in the south of Caspian Sea in Iran
• Hnúkaþeyr in Icelandic.

The Santa Ana winds of southern California are in some ways similar to the Föhn, but originate in dry deserts as a katabatic wind.

In popular culture

• Peter Camenzind, a novel by Hermann Hesse refers, at length, to the Alpine Föhn.
• 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 protagonists Ayla and Jondalar in Jean M. Auel's The Plains Of Passage over a glacier before the spring melt. The pair make references to the mood altering phenomena of the wind, similar to those of the Santa Ana wind.
• In Southern Germany, this wind is suppose to cause disturbed mood. Heinrich Hoffmann in his book "Hitler Was My Friend" notes that on the evening of September 18, 1931 when Adolf Hitler and Hoffmann left their Munich apartment on a election campaign tour, Hitler had complained about a bad mood and feeling. Hoffmann did try to pacify Hitler about the Austrian Föhn wind as the possible reason. Hours later, Hitler's niece, Geli Raubal was found dead in his Munich apartment. It was declared that she had committed suicide though it had conflicting testimonies from the witneseses present.

Fön trademark

AEG registered the trademark Fön in 1908 for its hairdryer. The word became a genericized trademark and is now, with varying spelling, the standard term for "hairdryer" in several languages, such as Finnish, German, Swiss German, Danish, Italian, Dutch, Norwegian, Czech, Croatian, Latvian, Romanian, Hebrew, Slovak, Slovenian, Swedish, Russian, Ukrainian, Turkish and Swiss French.

See also

• Katabatic winds
• Rain shadow
• Chinook wind

References

• McKnight, TL & Hess, Darrel (2000). Foehn/Chinoonk Winds. In , Physical Geography: A Landscape Appreciation, pp. 132. Upper Saddle River, NJ: Prentice Hall. ISBN 0130202630

Footnotes

External links

• Illustration
• Movie of a Foehn situation in the Swiss Alps