Definizione da National Snow and Ice Data Center, dove non è affatto definito come il vento che spira in quel di Trieste:
boraa cold wind blowing down an incline; a kind of katabatic wind.
Fonte:
http://nsidc.org/snow/glossary.htmlMi sembra incontestabile che sia un vento che spira in varie zone non dipendente solo dalla direzione:
http://en.wikipedia.org/wiki/Bora_(wind)
Bora or Bura (Bosnian: bura, Croatian: bura, Slovene: burja, Bulgarian: буран, Greek: βοράς, Turkish: bora) is a northern to north-eastern katabatic wind in the Adriatic, Bosnia and Herzegovina, Croatia, Montenegro, Italy, Greece, Slovenia, and Turkey.
The same root is found in the name of the Greek mythological figure of Boreas/Βορέας, the North Wind. Historical linguists speculate that the name may derive from a Proto-Indo-European root *gworh- meaning mountain.[1])
In Greek apart exists also the word "bora" (μπόρα) that describe an intense summer rain that lasts for a few minutes. In Albanian the word "bora" means snow.
Features
Bora on Molo Audace in Trieste, February 2011
The changeable Bora can often be felt all over Dalmatia, Istria, the Slovenian Littoral, Trieste, and the rest of the Adriatic east coast. It blows in gusts. The Bora is most common during the winter. It blows hardest, as the meteorologist Baron Ferdinand von Wrangel explained it by extending Julius Hann's explanation of Alpine katabatic winds to the north Adriatic,[2] when a polar high-pressure area sits over the snow-covered mountains of the interior plateau behind the Dinaric coastal mountain range and a calm low-pressure area lies further south over the warmer Adriatic. As the air grows even colder and thus denser at night, the Bora increases. Its initial temperature is so low that even with the warming occasioned by its descent it reaches the lowlands as a cold wind.[3] The wind takes two different traditional names depending on associated meteorological conditions: the "light bora" (Italian: Bora chiara) is Bora in the presence of clear skies, whereas clouds gathering on the hilltops and moving towards the seaside with rain characterize the "dark bora" (Bora scura).
The area where some of the strongest bora winds occur is the Velebit mountain range in Croatia. This seaside mountain chain, spanning 145 kilometers, represents a huge weather and climatic divide between the sharp continental climate of the interior, characterized by significant day/night temperature differences throughout the year, and the Adriatic coast, with a Mediterranean climate. Bora occurs because these two divided masses tend to equalize. Sailing can be extremely dangerous for an unexperienced navigator in the Velebit channel because the wind can start suddenly on a clear and calm day and result in major problems, frequently also affecting road traffic. Near the towns of Senj, Stara Novalja, Karlobag and the southern portal of the Sveti Rok Tunnel in Croatia, it can reach speeds of up to 220 kilometers per hour. On December 21, 1998 the speed of a gust on the Maslenica Bridge (north of Zadar) was measured at a record speed of 248 kilometres per hour.[4]
The bora on the Kras, depicted in Valvasor's The Glory of the Duchy of Carniola, 17th century
The wind is also an integral feature of Slovenia's Vipava Valley and Kras region (known as Carso in Italy), an area of limestone heights over the Gulf of Trieste stretching towards the Istrian peninsula. Because the region separates the lower Adriatic coast from the Julian Alps range, extreme bora winds often occur there. They have influenced the region's traditional lifestyle and architecture. Towns on the coast, where the Bora also frequently occurs, are built densely with narrow streets in part because of the wind. Buildings in several towns and villages in Slovenia and the Province of Trieste (Italy) have stones on their roofs to prevent the roof tiles from being blown off. Chains and ropes are occasionally stretched along the sidewalks in downtown Trieste, Italy, to facilitate pedestrian traffic - gusts in the city are usually above 120 km/h reaching to maxima of near 200 km/h. A strong bora will often be reported on Italian television news. Slovenian towns where the strongest bora occurs are Ajdovščina, Vipava and, to a lesser extent, Nova Gorica.
Strong bora winds also occur in the Tsemes Bay of the Black Sea near the Russian port of Novorossiysk, where they are known as nordost. They can reach speeds of up to 220 kilometres per hour.
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) indipendentemente da dove essi si trovino in quel momento...
. La bora è Trieste!