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a week.[5]

1 The cause of the mistral

Mistral wind blowing near . In the centre is the Château d'If

The mistral (Catalan: Mestral, Greek: Μαΐστρος) is a strong, cold, northwesterly wind that blows from southern into the in the - ern Mediterranean, with sustained often exceeding forty kilometers per hour, sometimes reaching one hun- dred kilometers per hour.[1] It is most common in the win- A showing the force of the mistral one day in November ter and spring, and strongest in the transition between the 2008. The wind reached a speed of 80 km/h (50 mph), with two seasons. Periods of the wind exceeding thirty kilo- average speeds of more than 50 km/h (31 mph) an hour near meters an hour for more than sixty-five hours have been Marseille. reported.[2] The mistral takes place each time there is an anticyclone, In France, it refers to a violent, cold, north or northwest or area of high pressure, in the Bay of Biscay, and an area wind that accelerates when it passes through the valleys of low pressure around the Gulf of . When this of the Rhone and the Rivers to the coast of the [3] happens, the flow of air between the high and low pres- Mediterranean around the Camargue region. It affects sure areas draws in a current of cold air from the north the northeast of the plain of and to which accelerates through the lower elevations between the of , where it is felt as a strong wind. It the foothills of the and the Cevennes. The condi- has a major influence all along the Mediterranean coast of tions for a mistral are even more favorable when a cold France, and often causes sudden storms in the Mediter- rainy front has crossed France from the northwest to the ranean between and the .[4] southeast as far as the Mediterranean. This cold, dry wind The name mistral comes from the Languedoc dialect of usually causes a period of cloudless skies and luminous the Occitan and means “masterly”. The same wind is sunshine, which gives the mistral its reputation for mak- called mistrau in the Provençal variant of Occitan, mestral ing the sky especially clear. There is also, however, the in Catalan, maestrale in Italian and Corsican, maistràle or mistral noir, which brings clouds and rain. The mistral bentu maestru in Sardinian, and majjistral in Maltese. noir occurs when the Azores High is extended and draws [5] The mistral is usually accompanied by clear, fresh in unusually moist air from the northwest. weather, and it plays an important role in creating the The long and enclosed shape of the Rhone Valley, and climate of Provence. It can reach speeds of more than the Venturi effect of funnelling the air through a narrow- ninety kilometers an hour, particularly in the Rhone Val- ing space, is frequently cited as the reason for the speed ley. Its average speed during the day can reach about fifty and force of the mistral, but the reasons are apparently kilometers an hour, calming noticeably at night. The mis- more complex. The mistral reaches its maximum speed tral usually blows in winter or spring, though it occurs in not at the narrowest part of the Rhone Valley, of all seasons. It sometimes lasts only one or two days, fre- Valence, but much farther south, where the Valley has quently lasts several days, and sometimes lasts more than widened. Also, the wind occurs not just in the Valley,

1 2 2 THE EFFECTS OF THE MISTRAL

but high above in the atmosphere, up to the troposphere, is not so cold and the wind only affects the plain of the three kilometres (1.9 miles) above the . The mis- Rhone delta and the Côte d'Azur. The good weather is tral is very strong at the summit of , 1900 confined to the coast of the Mediterranean, while it can meters in elevation, though the plain below is very wide. rain in the interior. The Côte d'Azur generally has a clear Other contributing factors to the strength of the mistral sky and warmer temperatures. This type of mistral usu- are the accumulation of masses of cold air, whose volume ally blows for no more than one to three days. is greater, pouring down the mountains and valleys to the The mistral originating from the northeast has a very dif- lower elevations. This is similar to a , but un- ferent character; it is felt only in the west of Provence and like a foehn wind the descent in altitude does not signif- as far as , with the wind coming from either a icantly warm the mistral. The causes and characteristics northerly or north-northeasterly direction. In the winter of the mistral are very similar to those of the , [6] this is by far the coldest form of the mistral. The wind can another wind of the French Mediterranean region. blow for more than a week. This kind of mistral is often connected with a low pressure area in the Gulf of Genoa, and it can bring unstable weather to the Côte d'Azur and the east of Provence, sometimes bringing heavy snow to low altitudes in winter. When the flow of air comes from the northeast due to a widespread low pressure area over the Atlantic and atmo- spheric disturbances over France, the air is even colder at both high altitudes and ground level, and the mistral is even stronger, and the weather worse, with the creation of cumulus clouds bringing weak storms. This kind of mistral is weaker in the east of Provence and the Côte d'Azur. The mistral is not always synonymous with clear skies. When a low pressure front over the Mediterranean ap- proaches the coast from the southeast, the weather can change quickly for the worse, and the mistral and its clear sky changes rapidly to an east wind bringing humid air and threatening clouds. The position of the low-pressure front creates a flow of air from the northwest or the north- east, channeled through the Rhone Valley. If this low- pressure area moves back toward the southeast, the mis- tral will quickly clear the air and the good weather will re- turn; but if the cold-weather front continues to approach the land, bad weather will continue for several days in the The bell tower of the hilltop village of La Cadière-d'Azur is open, entire Mediterranean basin, sometimes transforming into which allows the mistral to pass through. what French meteorologists call an épisode cévenol, a suc- cession of torrential rains and floods, particularly in the areas west of the Rhone Valley: the Ardèche, the , In France, the mistral particularly affects Provence, Hérault and Lozère.[7] Languedoc east of Montpellier, as well as all of the Rhone Valley from to Marseille, and as far southeast as The summer mistral, unlike the others, is created by Corsica and . The mistral usually blows from purely local conditions. It usually happens in July, and the north or northwest, but in certain pre-alpine valleys only in the valley of the Rhone and on the coast of and along the Côte d'Azur, the wind is channelled by the Provence. It is caused by a thermal depression over mountains so that it blows from east to west. Sometimes the interior of Provence (The Var and Alpes de Haute- it also blows from the north-north-east toward the east of Provence), created when the land is overheated. This Languedoc as far as Cap Béar. Frequently, the mistral creates a flow of air from the north toward the east of will affect only one part of the region. Provence. This wind is frequently cancelled out close to the coast by the breezes from the sea. It does not blow for In the Languedoc area, where the tramontane is the more than a single day, but it is feared in Provence, be- strongest wind, the mistral and the tramontane blow to- cause it dries the vegetation and it can spread forest fires. gether onto the Gulf of Lion and the northwest of the western Mediterranean, and can be felt to the east of the Balearic Islands, in Sardinia, and sometimes as far as the coast of Africa. When the mistral blows from the west, the mass of air 2.1 The effects of the mistral beyond France 3

As summer visitors to the beach in Provence learn, the summer mistral can quickly lower the temperature of the sea, as the wind pushes the warm water near the surface out to sea and it is replaced by colder water from greater depths.

2.1 The effects of the mistral beyond France

2 The effects of the mistral

The mistral helps explain the unusually sunny climate Oak bent to the south by the mistral in Sardinia (2700 to 2900 hours of sunshine a year) and clarity of the air of Provence. When other parts of France have clouds and storms, Provence is rarely affected for long, since the The mistral can affect the weather in North Africa, mistral quickly clears the sky. In less than two hours, the and or throughout the Mediterranean, particularly sky can change from completely covered to completely when low-pressure areas form in the Gulf of Genoa. clear. The mistral also blows away the dust, and makes the air particularly clear, so that during the mistral it is possible to see mountains 150 kilometres (93 miles) and 3 Maestral or maestro in the Adri- farther away. This clarity of the air and light is one of the features that attracted many French impressionist and atic post-impressionist artists to the South of France.[7] Similar names—maestral or maestro—are used for (al- The mistral has the reputation of bringing good health, though also mostly northwestern) a quite different wind in since the dry air dries stagnant water and the mud, giv- the . It is an anabatic sea-breeze wind which ing the mistral the local name mange-fange (Eng. “mud- blows in the summer when the east Adriatic coast gets eater”). It also blows away pollution from the skies over warmer than the sea. It is thus a mild sea-to-coast wind, the large cities and industrial areas.[7] unlike the mistral. The strong katabatic wind there is the The sunshine and dryness brought by the mistral have an northeastern . important effect on the local vegetation. The vegetation In it is also known as maïstros or maïstráli and in Provence, which is already dry because of the small south-western Crete it is considered the most beneficial amount of rainfall, is made even drier by the wind, which wind, said to blow only in daytime. makes it particularly susceptible to fires, which the wind spreads very rapidly, sometimes devastating vast expanses of mountainside before being extinguished. During the summer, thousands of hectares can burn when the mistral 4 The mistral in Provençal culture is blowing. In the Rhone Valley and on the plain of la Crau, the reg- The mistral played an important part in the life and cul- ularity and force of the mistral causes the trees to grow ture of Provence from the beginning. Excavations at the leaning to the south. Once the forest has been razed by prehistoric site called Terra Amata, at the foot of Mount fire, the strong wind makes it difficult for new trees to Boron in , showed that in about 400,000 B.C. the in- grow. The farmers of the Rhone Valley have long planted habitants had built a low wall of rocks and beach stones to the northwest of their fireplace to protect their fire from rows of cypress trees to shelter their crops from the dry [8] force of the mistral. The mistral can also have beneficial the power of the mistral. effects—the moving air can save crops from the spring The mas (farmhouse) traditionally faces south, with its frost, which can last until the end of April.[7] back to the mistral. The bell towers of villages in 4 7 BIBLIOGRAPHY

• (wind) • Levantades • • (wind) • • • Tramontane •

6 References

[1] http://www.nrlmry.navy.mil/sat_training/world_wind_ regimes/mistral/index.html Mediterranean Mistral Tuto- rial, World Wind Regimes, Naval Research Laboratory Monterey, accessed March 30, 2014.

A traditional Provençal santon, or Christmas creche figure, from [2] U.S. Naval Research Laboratory, Marine Meteorologial , facing the mistral Division

[3] The Petit Larousse Illustre (1997), defines Mistral as “Vent violent, froid, turbulent et sec qui souffle du secteur nord” (Violent, cold, turbulent and dry wind which blows from the north)". See also definition of Meteo France on their website and the U.S. Navy Marine Meteorology site, which describe the mistral as a strong, cold northwesterly wind

[4] Definition from the Website of Meteo France, the national weather service of the French government. (see external links.)

[5] Internet site of Meteo France, article on the mistral.

A Marseille santon of a Provençal shepherd in the mistral [6] Site of Meteo France

[7] Jean Vialar, Les vents régionaux et locaux, 1948, repub- Provence are often open iron frameworks, which allow lished by Météo-France in 2003 the wind to pass through. The traditional Provençal usually includes a figure of a shepherd [8] Henry de Lumley, :La Grande Histoire des premiers holding his hat, with his cloak blowing in the mistral. hommes europeens, Odile Jacob publishers, 2007. Pg. 225.

5 See also • 7 Bibliography Bora (wind) • • Cers (wind) Jean Vialar, Les vents régionaux et locaux, 1948, re- • published by Météo-France in 2003 • • La Grande Histoire des premiers Henry de Lumley, hommes europeéns, Odile Jacob, 2007.(ISBN 978- • Khamaseen 2-7381-2386-2) 5

8 External links • Local Mediterranean winds • Name of Winds • US Navy Marine Meteorology - Mediterranean Mis- tral Tutorial 6 9 TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES

9 Text and image sources, contributors, and licenses

9.1 Text • Mistral (wind) Source: https://en.wikipedia.org/wiki/Mistral_(wind)?oldid=676916172 Contributors: Olivier, Michael Hardy, Ellywa, An- dres, Evercat, Zoicon5, Sabbut, Joy, Robbot, Romanm, Gwalla, Mintleaf~enwiki, Chowbok, Thorwald, ChrisErbach, Rama, Notinasnaid, Etz Haim, Redlentil, Nk, LtNOWIS, Gene Nygaard, Woohookitty, LostAccount, Percy Snoodle, Mlewan, Farialima, Thomas Arelatensis, Margosbot~enwiki, Roboto de Ajvol, YurikBot, RussBot, Hede2000, Gaius Cornelius, Grafen, Bjrobinson, MCB, Spacebirdy, Ray Chason, Samoano~enwiki, KnightRider~enwiki, SmackBot, Roger Davies, IstvanWolf, Gabor Kertesz~enwiki, Armeria, Amatulic, Colonies Chris, Bruce Marlin, John C PI, Ian Spackman, Robofish, Thegreatdr, Frokor, Symposiarch, Runningonbrains, Marek69, Mpprh, Vhorvat, Manu bcn, JAnDbot, Phorse, Magioladitis, CommonsDelinker, KTo288, Kudpung, Inwind, UnicornTapestry, Caesaraix, Kr-val, CanOfWorms, SieBot, ToePeu.bot, SiefkinDR, LarRan, Nylad, Arjayay, WikHead, Catgirl, Addbot, Loralie, Underwaterbuffalo, Ktrungthuy, Roman- skolduns, Luckas-bot, Yobot, J04n, GrouchoBot, Foreverprovence, Thehelpfulbot, Bmclaughlin9, Vrenator, Brucarney, ฀฀, NLykiardop- ulo, EmausBot, ZéroBot, Suslindisambiguator, ClueBot NG, Dkueter, Widr, MerlIwBot, SpencerM, Ella Plantagenet, JephthahsDaughter, ChemTerm, Julietdeltalima and Anonymous: 69

9.2 Images • File:Bell_Tower_La_Cadiere_d'Azur_Provence_France.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/65/Bell_ Tower_La_Cadiere_d%27Azur_Provence_France.jpg License: Public domain Contributors: Own work Original artist: SiefkinDR • File:Carte_du_mistral.png Source: https://upload.wikimedia.org/wikipedia/commons/f/f6/Carte_du_mistral.png License: CC BY-SA 3.0 Contributors: Données météorologiques du 13 novembre 2008 à midi (carte de France sur Commons.) Original artist: Vi..Cult... • File:Gebogene_Korkeiche.jpg Source: https://upload.wikimedia.org/wikipedia/commons/6/6a/Gebogene_Korkeiche.jpg License: CC- BY-SA-3.0 Contributors: Stahlkochers collection Original artist: Nick Stahlkocher • File:Mistral_sur_le_Frioul.JPG Source: https://upload.wikimedia.org/wikipedia/commons/5/54/Mistral_sur_le_Frioul.JPG License: Public domain Contributors: Self-photographed Original artist: Vincent • File:Mistral_wind1.jpg Source: https://upload.wikimedia.org/wikipedia/commons/7/7f/Mistral_wind1.jpg License: Public domain Con- tributors: ? Original artist: ? • File:Provence_Mistral_Santon.jpg Source: https://upload.wikimedia.org/wikipedia/commons/2/2f/Provence_Mistral_Santon.jpg Li- cense: Public domain Contributors: Own work Original artist: Marie blanche Sorribas • File:Santon_in_Mistral_Wind_Arles.jpg Source: https://upload.wikimedia.org/wikipedia/commons/9/94/Santon_in_Mistral_Wind_ Arles.jpg License: Public domain Contributors: Own work Original artist: SiefkinDR • File:Wikisource-logo.svg Source: https://upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg License: CC BY-SA 3.0 Contributors: Rei-artur Original artist: Nicholas Moreau • File:_Brosen_windrose.svg Source: https://upload.wikimedia.org/wikipedia/commons/1/1a/Brosen_windrose.svg License: CC BY 2.5 Contributors: Own work Original artist: Brosen

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