The cierzo is a strong, dry and usually cold wind that blows from the North or Northwest through the regions of Aragon,

La Rioja La Rioja () is an autonomous community and province in Spain, in the north of the Iberian Peninsula. Its capital is Logroño. Other cities and towns in the province include Calahorra, Arnedo, Alfaro, Haro, Santo Domingo de la Calzada, an ...

and

Navarra Navarre (; es, Navarra ; eu, Nafarroa ), officially the Chartered Community of Navarre ( es, Comunidad Foral de Navarra, links=no ; eu, Nafarroako Foru Komunitatea, links=no ), is a foral autonomous community and province in northern Spain, ...

in the

Ebro valley , name_etymology = , image = Zaragoza shel.JPG , image_size = , image_caption = The Ebro River in Zaragoza , map = SpainEbroBasin.png , map_size = , map_caption = The Ebro ...

in Spain. It takes place when there is an

anticyclone An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from ...

in the Bay of Biscay and a

low-pressure area In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...

in the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

. On February 17, 1954, a gust with direction 290 of 135 km/h was recorded at the Zaragoza Airport observatory. It is known since ancient times, and its name stems from the Latin word ''circius'', which probably came from an Iberian word.

Cato the Elder Marcus Porcius Cato (; 234–149 BC), also known as Cato the Censor ( la, Censorius), the Elder and the Wise, was a Roman soldier, senator, and historian known for his conservatism and opposition to Hellenization. He was the first to write his ...

described it in the 2nd century BC as "a wind that fills your mouth and tumbles waggons and armed men."R. Riosalido, L. Vazquez, A. Gordo and A. Jansa
«'CIERZO': NORTHWESTERLY WIND ALONG THE EBRO VALLEY AS A MESO-SCALE EFFECT INDUCED ON THE LEE OF THE PYRENEES MOUNTAIN RANGE; A CASE STUDY DURING ALPEX SPECIAL OBSERVING PERIOD.»
''Scientific results of the Alpine experiment (ALPEX)-VOLUME II, GARP publication series No. 27, WMO/TD No. 108'' It reaches a speed of more than 100 km/h several times each year. Its maximum recorded speed has been 160 km/h in July 1956. It is more usual in autumn and winter, when larger pressure gradients take place, but a small pressure difference along the Ebro valley is sufficient to initiate a cierzo wind in any season. The cierzo wind is similar to the

mistral Mistral may refer to: * Mistral (wind) in southern France and Sardinia Automobiles * Maserati Mistral, a Maserati grand tourer produced from 1963 until 1970 * Nissan Mistral, or Terrano II, a Nissan 4×4 produced from 1993 until 2006 * Microp ...

of the Rhone valley in

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

or the bora in the Balcans. The cierzo conditions life in the Ebro Valley because it is a drying wind and plants must fight against the dryness that the cierzo produces in the climate. Likewise, farmers must protect their orchard crops with reed barriers or tree plantations, which are called pareteras de caña, enramadas, abrigaños or bardos.

References

Winds {{weather-stub