Föhn wind
Encyclopedia
Rain shadow
A rain shadow is a dry area on the lee side of a mountainous area. The mountains block the passage of rain-producing weather systems, casting a "shadow" of dryness behind them. As shown by the diagram to the right, the warm moist air is "pulled" by the prevailing winds over a mountain...
wind that results from the subsequent adiabatic warming of air that has dropped most of its moisture on windward slopes (see orographic lift
Orographic lift
Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it quickly cools down adiabatically, which can raise the relative humidity to 100% and create clouds and, under the right conditions,...
). As a consequence of the different adiabatic lapse rate
Lapse rate
The lapse rate is defined as the rate of decrease with height for an atmospheric variable. The variable involved is temperature unless specified otherwise. The terminology arises from the word lapse in the sense of a decrease or decline; thus, the lapse rate is the rate of decrease with height and...
s of moist and dry air, the air on the leeward slopes becomes warmer than equivalent elevations on the windward slopes. Föhn winds can raise temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
s by as much as 30 °C (54 °F) in just a matter of hours. Central Europe
Central Europe
Central Europe or alternatively Middle Europe is a region of the European continent lying between the variously defined areas of Eastern and Western Europe...
enjoys a warmer climate due to the Föhn, as moist winds off the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
blow over the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
.
Effects
Winds of this type are called "snow-eaters" for their ability to make snowSnow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
melt
Melt
Melt can refer to:* Melting, in physics, the process of heating a solid substance to a liquid*Melt , the semi-liquid material used in steelmaking and glassblowing*Melt inclusions, a feature of igneous rock...
or sublimate rapidly. This snow-removing ability is caused not only by warmer temperatures, but also the low relative humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
of the air mass having been stripped of moisture by orographic precipitation
Orographic lift
Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it quickly cools down adiabatically, which can raise the relative humidity to 100% and create clouds and, under the right conditions,...
coming over the mountain(s).
Föhn winds are notorious among mountaineer
Mountaineer
-Sports:*Mountaineering, the sport, hobby or profession of walking, hiking, trekking and climbing up mountains, also known as alpinism-University athletic teams and mascots:*Appalachian State Mountaineers, the athletic teams of Appalachian State University...
s in the Alps, especially those climbing the Eiger
Eiger
The Eiger is a mountain in the Bernese Alps in Switzerland. It is the easternmost peak of a ridge crest that extends across the Mönch to the Jungfrau at 4,158 m...
, for whom the winds add further difficulty in ascending an already difficult peak.
They are also associated with the rapid spread of wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
s, 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 19th century. 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.
The cause of warm, dry conditions on the lee side
The condition exists because warm moist air rises through "orographic lifting" up and over the top of a mountain range or large mountain. Because of decreasing atmospheric pressure with increasing altitude, the air expanded and adiabatically cooled at the dry adiabatic lapse rate to the point that the air reaches its adiabatic dew pointDew point
The dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into liquid water. The condensed water is called dew when it forms on a solid surface. The dew point is a saturation temperature.The dew point is...
(which is not the same as its constant pressure
Isobaric process
An isobaric process is a thermodynamic process in which the pressure stays constant. The term derives from the Greek isos, , and barus,...
dew point commonly reported in weather forecasts). Upon reaching the adiabatic dew point, water vapor in the air begins to condense, with the release of latent heat
Latent heat
Latent heat is the heat released or absorbed by a chemical substance or a thermodynamic system during a process that occurs without a change in temperature. A typical example is a change of state of matter, meaning a phase transition such as the melting of ice or the boiling of water. The term was...
from condensation
Condensation
Condensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
slowing the overall rate of adiabatic cooling of the air to the saturated adiabatic lapse rate as the air continues to rise. Condensation is also commonly followed by precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
on the top and windward sides of the mountain. As the air descends on the leeward side, it is warmed by adiabatic compression at the dry adiabatic lapse rate. Because the air has lost much of its original water vapor content, the descending air creates an arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
region on the leeward side of the mountain.
Etymology
The name föhn originated in the alpine regionAlps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
. From Latin (ventus) favonius, a mild west wind of which Favonius was the Roman personification. The German word "Fön" (without the "H", but pronounced the same way), a genericized trademark
Genericized trademark
A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...
, is also used to mean "hairdryer".
Local examples
Regionally, these winds are known by many different names. These include:- Föhn in AustriaAustriaAustria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
, southern GermanyGermanyGermany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, and German-speaking regions of SwitzerlandSwitzerlandSwitzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
, LiechtensteinLiechtensteinThe Principality of Liechtenstein is a doubly landlocked alpine country in Central Europe, bordered by Switzerland to the west and south and by Austria to the east. Its area is just over , and it has an estimated population of 35,000. Its capital is Vaduz. The biggest town is Schaan...
and Northern ItalyNorthern ItalyNorthern Italy is a wide cultural, historical and geographical definition, without any administrative usage, used to indicate the northern part of the Italian state, also referred as Settentrione or Alta Italia...
(even non-German-speaking regions) - BergwindBergwindBergwind is the South African name for a foehn wind, a hot dry wind blowing from the mountainous interior to the coast. It varies from mild to gusts up to 100km/h that cause structural damage...
in South AfricaSouth AfricaThe Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans... - Chinook windChinook windChinook winds , often called chinooks, commonly refers to foehn winds in the interior West of North America, where the Canadian Prairies and Great Plains meet various mountain ranges, although the original usage is in reference to wet, warm coastal winds in the Pacific Northwest.Chinook is claimed...
s east of the Rocky MountainsRocky MountainsThe Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
in the United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
and CanadaCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, and north, east and west of the Chugach MountainsChugach MountainsThe Chugach Mountains of southern Alaska are the northernmost of the several mountain ranges that make up the Pacific Coast Ranges of the western edge of North America. The range is about 500 km long, running generally east-west. Its highest point is Mount Marcus Baker, at , but most of its...
of AlaskaAlaskaAlaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, United States - Favonio in TicinoTicinoCanton Ticino or Ticino is the southernmost canton of Switzerland. Named after the Ticino river, it is the only canton in which Italian is the sole official language...
and Italy - Fogony in the CatalanCataloniaCatalonia is an autonomous community in northeastern Spain, with the official status of a "nationality" of Spain. Catalonia comprises four provinces: Barcelona, Girona, Lleida, and Tarragona. Its capital and largest city is Barcelona. Catalonia covers an area of 32,114 km² and has an...
PyreneesPyreneesThe Pyrenees is a range of mountains in southwest Europe that forms a natural border between France and Spain... - Föhn in Wollongong and South Coast, NSW, Australia. Often associated with heavy orographic lifiting on the windward side of the escarpment
- Garmoosh, Garmesh, Garmbaad (Warm Wind): in Gilan region, in the south of Caspian SeaCaspian SeaThe Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
in IranIranIran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia... - HalnyHalnyHalny – a foehn wind that blows in southern Poland and in Slovakia in the Carpathian Mountains. The most turbulent halny blows in Podhale, coming from the South, down the slopes of the Tatra Mountains; in Slovakia, on the other side of the mountains, it comes from the North.Halny is a warm...
in the Carpathian MountainsCarpathian MountainsThe Carpathian Mountains or Carpathians are a range of mountains forming an arc roughly long across Central and Eastern Europe, making them the second-longest mountain range in Europe...
, Central Europe - The Helm windHelm WindThe Helm Wind is a named wind in Cumbria, England, a strong north-easterly wind which blows down the south-west slope of the Cross Fell escarpment. It is the only named wind in the British Isles, although many other mountain regions in Britain exhibit the same phenomenon when the weather conditions...
, on the PenninesPenninesThe Pennines are a low-rising mountain range, separating the North West of England from Yorkshire and the North East.Often described as the "backbone of England", they form a more-or-less continuous range stretching from the Peak District in Derbyshire, around the northern and eastern edges of...
in the Eden ValleyEden ValleyEden Valley may refer to:* the valley of various rivers called River Eden* Eden Valley 216 in Alberta, Canada* Eden Valley in Mendocino County* Eden Valley, South Australia in Australia* Eden Valley, Minnesota in the United States of America...
, CumbriaCumbriaCumbria , is a non-metropolitan county in North West England. The county and Cumbria County Council, its local authority, came into existence in 1974 after the passage of the Local Government Act 1972. Cumbria's largest settlement and county town is Carlisle. It consists of six districts, and in...
, EnglandEnglandEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental... - Hnúkaþeyr in IcelandicIcelandic languageIcelandic is a North Germanic language, the main language of Iceland. Its closest relative is Faroese.Icelandic is an Indo-European language belonging to the North Germanic or Nordic branch of the Germanic languages. Historically, it was the westernmost of the Indo-European languages prior to the...
- Lyvas wind in Elefsina and AthensAthensAthens , is the capital and largest city of Greece. Athens dominates the Attica region and is one of the world's oldest cities, as its recorded history spans around 3,400 years. Classical Athens was a powerful city-state...
in GreeceGreeceGreece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe.... - The Nor'westerNor'west archThe Nor'west arch is a weather pattern peculiar to the east coast of New Zealand's South Island. For this reason, it is also often referred to as the Canterbury arch. It is shown in an apparent arch of high white cloud in an otherwise clear blue sky over the Southern Alps, and is accompanied by a...
in Hawkes Bay, Canterbury, and OtagoOtagoOtago is a region of New Zealand in the south of the South Island. The region covers an area of approximately making it the country's second largest region. The population of Otago is...
, New ZealandNew ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga... - Puelche windPuelche (wind)A Puelche wind is a dry foehn-like eastern wind that occurs in south-central Chile. The wind owns its name from the Puelche people that inhabited the eastern slopes of the Andes. Puelche is mainly caused by South Pacific high pressure extending eastwards across the Andes and/or building a ridge to...
in Chile - Terral in MálagaMálagaMálaga is a city and a municipality in the Autonomous Community of Andalusia, Spain. With a population of 568,507 in 2010, it is the second most populous city of Andalusia and the sixth largest in Spain. This is the southernmost large city in Europe...
(southern SpainSpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
) - Vântul Mare in the Carpathian MountainsCarpathian MountainsThe Carpathian Mountains or Carpathians are a range of mountains forming an arc roughly long across Central and Eastern Europe, making them the second-longest mountain range in Europe...
, RomaniaRomaniaRomania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea... - Viento del Sur (Southern Wind) in the Cantabrian regionGreen SpainGreen Spain is the name given to the Spanish northern maritime façade exposed to the Atlantic Ocean in Galicia which also runs along the coastal strip lying north of the Cantabrian and Basque mountains, along the Bay of Biscay...
(northern SpainSpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
) - Zonda windZonda windZonda wind is a regional term for the foehn wind that often occurs on the eastern slope of the Andes, in Argentina. The Zonda is a dry wind which comes from the polar maritime air, warmed by descent from the crest, which is some 6,000 m above sea level...
s in ArgentinaArgentinaArgentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
The Santa Ana winds of southern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, including the Sundowner
Sundowner
Sundowner may refer to:* Sundowner , a model of Mazda truck* Sundowner , the solo acoustic project of Chris McCaughan* Sundowner , an alcoholic cocktail* Sundowner , a model of Beechcraft airplane...
winds of Santa Barbara, are in some ways similar to the Föhn, but originate in dry deserts as a katabatic wind
Katabatic wind
A katabatic wind, from the Greek word katabatikos meaning "going downhill", is the technical name for a drainage wind, a wind that carries high density air from a higher elevation down a slope under the force of gravity. Such winds are sometimes also called fall winds...
.
In popular culture
- Peter CamenzindPeter CamenzindPeter Camenzind, published in 1904, was the first novel by Hermann Hesse and contains a number of themes that were to preoccupy many of Hesse's later works, most notably the individual's search for a unique spiritual and physical identity amidst the backdrops of nature and modern civilization and...
, a novel by Hermann HesseHermann HesseHermann Hesse was a German-Swiss poet, novelist, and painter. In 1946, he received the Nobel Prize in Literature...
, refers, at length, to the Alpine Föhn. - The Föhn is used for the letter F in "Crazy ABC's" from the album Snacktime!Snacktime!Snacktime! is the debut children's album by Canadian band Barenaked Ladies released on May 6, 2008. A companion book was written with artwork by multi-instrumentalist Kevin Hearn, who also contributed artwork for the album. It is the final Barenaked Ladies album to include Steven Page, who departed...
by the Barenaked LadiesBarenaked LadiesBarenaked Ladies is a Canadian alternative rock band. The band is currently composed of Jim Creeggan, Kevin Hearn, Ed Robertson, and Tyler Stewart. Barenaked Ladies formed in 1988 in Scarborough, Ontario, then a suburban municipality outside the City of Toronto...
. - The threat of the Föhn drives the protagonists Ayla and Jondalar in Jean M. AuelJean M. AuelJean Marie Auel is an American writer. She is best known for her Earth's Children books, a series of novels set in prehistoric Europe that explores interactions of Cro-Magnon people with Neanderthals...
's The Plains of PassageThe Plains of PassageThe Plains of Passage is an historical fiction novel by Jean M. Auel published in 1990. It is the sequel to The Mammoth Hunters and fourth in the Earth's Children series.-Plot summary:...
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 windSanta Ana windThe Santa Ana winds are strong, extremely dry offshore winds that characteristically sweep through Southern California and northern Baja California in late fall and winter. They can range from hot to cold, depending on the prevailing temperatures in the source regions, the Great Basin and upper...
. - In Southern Germany, this wind is supposed to cause disturbed mood. Heinrich HoffmannHeinrich HoffmannHeinrich Hoffmann was a German photographer best known for his many published photographs of Adolf Hitler.-Early life and career:...
notes in his book Hitler Was My Friend that on the evening of September 18, 1931, when Adolf HitlerAdolf HitlerAdolf Hitler was an Austrian-born German politician and the leader of the National Socialist German Workers Party , commonly referred to as the Nazi Party). He was Chancellor of Germany from 1933 to 1945, and head of state from 1934 to 1945...
and Hoffmann left their Munich apartment on an election campaign tour, Hitler had complained about a bad mood and feeling. Hoffmann tried to pacify Hitler about the Austrian Föhn wind as the possible reason. Hours later, Hitler's niece, Geli RaubalGeli RaubalAngelika Maria "Geli" Raubal was Adolf Hitler's half niece. Born in Linz, Austria-Hungary, she was the second child and eldest daughter of Leo Raubal Sr. and Hitler's half-sister, Angela Raubal...
, was found dead in his Munich apartment. It was declared that she had committed suicide though it had conflicting testimonies from the witnesses present. - It's mentioned as a surprise change in weather during the ascent of Switzerland's EigerEigerThe Eiger is a mountain in the Bernese Alps in Switzerland. It is the easternmost peak of a ridge crest that extends across the Mönch to the Jungfrau at 4,158 m...
in the book The Eiger SanctionThe Eiger SanctionThe Eiger Sanction is a 1972 thriller novel by Rodney William Whitaker, written under the pseudonym Trevanian. The story was made into a film directed by and starring Clint Eastwood in 1975.Whitaker wrote a sequel entitled The Loo Sanction....
by TrevanianTrevanianRodney William Whitaker was an American film scholar and writer who wrote several successful novels under the pen name Trevanian. Whitaker also published works as Nicholas Seare, Beñat Le Cagot and Edoard Moran...
. - The Föhn blowing through ZurichZürichZurich is the largest city in Switzerland and the capital of the canton of Zurich. It is located in central Switzerland at the northwestern tip of Lake Zurich...
torments the characters in Robert Anton WilsonRobert Anton WilsonRobert Anton Wilson , known to friends as "Bob", was an American author and polymath who became at various times a novelist, philosopher, psychologist, essayist, editor, playwright, poet, futurist, civil libertarian and self-described agnostic mystic...
's Masks of the IlluminatiMasks of the IlluminatiMasks of the Illuminati is a 1981 novel by Robert Anton Wilson, co-author of The Illuminatus! Trilogy and over thirty other influential books...
. - Joan Didion explores the nature of various Foehn winds in her essay "The Santa Ana".
- "Foehn" is a magic spell that deals wind/heat damage in Star Ocean: The Second StoryStar Ocean: The Second Storyis a action role-playing PlayStation video game developed by tri-Ace and published by Enix. It is the second game in the Star Ocean series and the first game in the series to be released in North America and Europe , courtesy of Sony Computer Entertainment...
.
Fön trademark
AEGAEG
Allgemeine Elektricitäts-Gesellschaft was a German producer of electrical equipment founded in 1883 by Emil Rathenau....
registered the trademark Fön in 1908 for its hairdryer. The word became a genericized trademark
Genericized trademark
A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...
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 windKatabatic windA katabatic wind, from the Greek word katabatikos meaning "going downhill", is the technical name for a drainage wind, a wind that carries high density air from a higher elevation down a slope under the force of gravity. Such winds are sometimes also called fall winds...
s - Lee wave
- Rain shadowRain shadowA rain shadow is a dry area on the lee side of a mountainous area. The mountains block the passage of rain-producing weather systems, casting a "shadow" of dryness behind them. As shown by the diagram to the right, the warm moist air is "pulled" by the prevailing winds over a mountain...
- Chinook windChinook windChinook winds , often called chinooks, commonly refers to foehn winds in the interior West of North America, where the Canadian Prairies and Great Plains meet various mountain ranges, although the original usage is in reference to wet, warm coastal winds in the Pacific Northwest.Chinook is claimed...
- MeteorologyMeteorologyMeteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
External links
- Photo of Föhnmauer The strong clouds at the mountain ridges where the Föhn winds form are called Föhnmauer (Föhn wall).
- Illustration
- Movie of a Föhn situation in the Swiss Alps