3st PART






STORM OF 2010 (Xynthia) IN FRANCE



Storms are after floods climate phenomenon that cause the most of damage. They can have a significant impact for both the man or his activities and the environment (trees fall on forests, habitat damages, ports...). The number of victims may be more or less important depending on the extent and power of the storm.

The consequences of storms are mainly economic. That means costs and losses or disruption to activities resulting from damage or destruction (private or public buildings, industrial or transport infrastructures, etc).

Both storms on December 1999 caused in France
the destruction of about 500 000 hectares of forest.


26 and 27/12/1999 France and neighboring countries have experienced one of the worst storms of the century. There were 88 deaths in France and about ten in Switzerland, Germany, Spain, Great Britain ..., 3.50 million homes without electricity or heating, hundreds of cars damaged by falling trees, tens of thousands of uprooted trees, more than 12 billion euros of damage and about 500,000 hectares of forest. Such events would occur about once every hundred years.

The first storm mainly shot in the north of France hiting first the Finisterre at 2 o'clock then Strasbourg at around 11 am. The pressure was 960 hPa at the center of the depression. From 12/25/1999 at about 6 pm to 12/26/1999 about 6 am it had an explosive development after passing under the jet stream that had winds near 400 km/h at 9000 m altitude, which certainly accentuated the widening of this depression and thus intensified winds. Gusts of wind blew up to 126 km/h in Dijon and Nantes, 144 km/h in Strasbourg, Chartres and Nancy, 148 km/h in Ploumanach and Troyes, 169 km/h in Paris-Montsouris and even 198 km/h Chassiron.

The second storm passed more southern circulating at the Loire with a pressure of 965 hPa and wind gusts up to 184 km/h in Ouessant Island, 173 km/h in Ile-de -France, and even more than 200 km/h on the Ile de Ré. It crossed the France moving at a speed close to 100 km/h. at about 19 pm local time it was over Nantes then at about 22 hours local time in Romorantin and the 12/28/1999 at 1:00 over Dijon in the morning.

The map atmospheric pressures recorded during the second storm


A video showing the power of the storm of 1999
Part of 2/5, part of 3/5, part of 4/5 and part of 5/5.


The damage from these storms

The ONF estimations for public forests show that the three most affected regions (in m3 of timber felled or broken) are Lorraine, Champagne-Ardennes, Alsace, Franche Comté.

Click here to enlarge


Spilled boats by the storm of December 1999


A pine forest ravaged by the storm of December 1999

THE STORM OF 2010 (Xynthia)

On the night of Saturday 27 to 28/02/2010 one of the most violent storm coming from the west of Portugal reached the France with 53 casualties and damage costing about € 1 billion, uprooting many trees,. winds of more 150.km/h were recorded in Charente-Maritime or even 200.km/h in the Pyrenees (over 237.km/h on the Pic du Midi at 2877 km of altitude) causing damage to ski resorts. In the spanish Basque Country some weather stations have recorded gusts 228.km/h in Roduna, 176.km/h in Cerroja...

Between :
The strong wind of the storm that led to the strong swell (about 8.00 meters of high at the strongest of the storm) and waves that pushed water from the ocean to the odds ;
- Then with the atmospheric pressure of the storm although low (970hpa) which further accentuated the storm surge (6 meters of high) that causes Ekman pumping and view the shape of the seabed ;
- And high tides (coefficient of 102) that occurred during the storm ;
behold levees gave way in several coastal cities in Charente-Maritime, Vendee... causing major flooding on 13.km inland. In addition some buildings were built 3,90 meters above the level of the sea which is a bit limited, given the rule of local urban development plan (PLU) that secures the building permit to 4 m above sea level (score based on Centenales floods). Then the boats were run aground the beach....


Here are 2 photos taken by photographer Philippe Cherel
one day after the storm Xynthia and another a year later.

The violence of this storm of unusual intensity at the end of winter is explained as those of 1999 by the presence much further south than usual a cold current at high altitude (jet stream), with westerly winds fast and very strong, and a warm air mass in low layer, around 1500 meters above the ground.

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