Ground wind

For a sailor, a wind of ground indicates a wind coming from the ground and blowing towards the broad one. Its opposite is the wind of sea .

When there is a ground wind, the maritime zone close to the east coast little agitated because the waves do not have time to be formed : it is the Fetch. If the coast comprises a little relief, the wind is partly stopped. The ground wind is thus favourable with the approach of the coast and the Mouillage of a ship in a shelter. It makes on the other hand dangerous navigation on board small boats (center-boards, boards with veil, engine boats) because it tends in the event of failures of the propulsion to draw aside the boat of the coast. The opposite of the ground wind is the wind of sea which blows broad towards the coast. If the wind of sea is strong, the sea which was formed with broad breaks close the coast as soon as the funds are raised: the arrival in the ports can become dangerous, the search for a shelter along the difficult east coast.

In certain cases the ground wind can be also dangerous for navigation: it is the phenomenon of the dreaded Williwaw of the sailors in the areas of the Patagonie and the Alaska; the wind, which goes down from mountainous solid masses, is strongly accelerated when it leads to the coast.

The wind in edge of coast can be locally modified in direction and force by the phenomenon of the thermal breezes. The incidence of these breezes depends on the solar hour and is particularly important during the summer when the sunning is with strongest. From day it results in a wind of sea which can be very strong in certain areas. From night the thermal breeze is a ground wind of a force generally weaker: to see Breeze of sea and Breaks ground.

On the French coast, the most important winds in the Mediterranean are ground winds it Mistral and the Tramontane - whereas on the coast Atlantique, the dominant winds, of Western sector, are winds of sea.

See too

Breeze of sea and Breaks ground

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