A north wind that blows down the Rhone valley south of Valence, France, and into the Gulf of Lions. It is strong, squally, cold, and dry, the combined result of the basic circulation, a fall wind, and jet-effect wind. It blows from the north or northwest in the Rhône Delta, where it is strongest, from northwest in Provence and from northeast in the valley of the Durance below Sisteron. A general mistral usually begins with the development of a depression over the Tyrrhenian Sea or Gulf of Genoa with an anticyclone advancing from the Azores to central France. It often exceeds 27 m s⁻¹ (60 mph) and reaches 38 m s⁻¹ (85 mph) in the lower Rhône valley and 22 m s⁻¹ (50 mph) at Marseilles, decreasing both east and west and out to sea. It remains strong to a height of 2–3 km. In the absence of a strong pressure gradient, a weaker katabatic local mistral develops in the Rhône valley. A general mistral usually lasts for several days, sometimes with short lulls. It is most violent in winter and spring, and may do considerable damage. Market gardens and orchards are protected from it by windbreaks, and rural houses are built with only a few openings on the side exposed to it. The mistral has a variety of local names: mangofango in Provence; sécaire, maistrau, maistre, or magistral in Cévennes; dramundan in Perpignan; cierzo in Spain; cers in the Pyrenees, etc. South of Mont Ventoux a similar wind is named bise. A local west wind of mistral type that descends from Mt. Canigou to the plains of Roussillon is called canigonenc. Compare bora, tramontana, maestro; see also cavaliers.