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Secrets of the St. Lawrence

Sailors take warning - The unexpected

Baie de Gaspé

- "I had just sailed in from the Îles de la Madeleine. I anchored on the West side of the wharf at Anse au Sauvage for shelter from the light waves coming from the East. The next morning, about 08:30, the wind shifted, picking up into a breeze from the

- "I checked my lines and went below to finish my breakfast. I had barely touched my coffee when the wind came gusting out of the West.

- "I just barely had time to get up on deck before the storm struck. I couldn't get away. I jumped onto the wharf and prayed to God that the wind would stop beating my boat against the side. What a storm!"

Sudden storms

Such storms blow up so suddenly that no one can see them coming.

This was the case at about 08:00 on the morning of September 3, 1980, when a low reached the western tip of Anticosti, at 983 millibars. This low pressure system marked the end of the explosive development of a rather insignificant low, observed at 22:00 the previous evening, at 1006 millibars, over Lac Saint-Jean. This development would have been difficult to predict.

The abrupt and steep drop in barometric pressure was the only obvious indication that such a violent phenomenon was about to occur. This example illustrates the importance of keeping a barometer or barograph where you can see it at all times.

Barometric pressure

If the pressure is falling at a rate of 1 millibar an hour and the wind is freshening, you should consult the latest forecast. If the pressure continues to fall or starts falling even more quickly, the weather is about to change drastically for the worse. DANGER!

Example of the observation at the Gaspé Airport of the sudden pressure drop on September 3, 1980. Representative of a sudden pressure drop from 1010 to 985 millibars in a few hours.

September 3, 1980. 3-hour pressure tendency and wind observation at Gaspé Airport, the day of the incident.

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