Although I have only reached page 12 of the book, I have already discovered the best account of the Mistral since I read The Count of Monte Cristo many moons ago. Peter Mayle in A Year in Provence describes it so:
"Meanwhile, a thousand miles to the north, the wind that had started in Siberia was picking up speed for the final part of its journey. We had heard stories about the Mistral, how it drives people, and animals, mad. It was an extenuating circumstance in crimes of violence.
"It blew for 15 days on end, uprooting trees, overturning cars, smashing windows, tossing elderly ladies into the gutter, splintering telegraph poles, moaning through houses like a cold baleful ghost, causing la grippe, domestic squabbles, absenteeism from work, toothache, migraine - every problem in Provence that couldn't be blamed on the politicians was the fault of the sacre vent, which the Provencaux spoke about with a kind of masochistic pride."
The Mistral, as we know, is a cold, dry, penetrating, parching wind that sweeps down the valley of the Rhone at intervals, most frequently in winter and in early spring. It is an unusual blend: a combination of what meteorologists call a "fall" wind and a "ravine" wind.
The process starts when large amounts of air cool through contact with a cold mountainside, and slide down to accumulate in the valleys of the French Alps and the Cevennes. There, these chilly stagnant reservoirs of air remain, often for some considerable time, waiting to overflow when the right conditions come along.
Then a trigger, in the form of a suitable pressure pattern, disturbs these mountain pools, and the result is a flash-flood of cold air cascading down the mountains into the valley of the Rhone. The "ravine" effect is the funnelling of the air which occurs as it is forced to flow southwards through the valley. Constrictions in this narrow channel result in dramatic increases in the wind speed, and cause the Mistral to be strong, blustery and often destructive.
"We were poorly prepared," continues Peter Mayle, "when the first Mistral of the year came howling down the Rhone Valley, turned left, and smacked into the west side of the house with enough force to skim roof tiles into the swimming pool.
"The temperature dropped 20 degrees in 24 hours. It went down to zero, and then six below. Readings in Marseilles showed a wind speed of 180 km/hour. And then one morning, with the sound of branches snapping, the pipes burst one after the other under the pressure of the water that had frozen in them overnight."