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Secrets of the St. Lawrence

The wind in your sails - Against the wall


- "We're coming up to the Péninsule de la Gaspésie. With those mountains and high cliffs, this Northwesterly wind will have to turn Westerly. If we stay offshore a few nautical miles, we should get to Mont-Louis a lot faster. With this wind, it would be a lot harder if we hugged the Charlevoix shore."


When the wind strikes a steep shore at an angle, it is deflected along the shoreline and strengthens. This increase in wind speed results as the air piles up.

The steeper the barrier, the stronger the wind and the more pronounced the effect. It may be felt as far as ten nautical miles off the Péninsule de la Gaspésie.

Close to the shore, the wind will be very turbulent because of this barrier effect.

Wind flow that hits the shoreline on an angle will intensify as its direction is consolidated. Very close to the shoreline wind will be very turbulent.


The situation is very different if the wind is blowing off the top of a cliff. The wind will blow toward the sea, but when it meets the sea it will eddy back toward the cliff just where you would have thought that you were sheltered from the wind.

Farther offshore, the wind will bounce along the water's surface for a distance of about 7 to 10 times the height of the cliff.

These eddy and bouncing effects create very turbulent winds.

Wind flow near a cliff will be turbulent near the cliff’s edge and alternately strong and light a distance of 7 to 10 times the height of the cliff out to sea.

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