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
the destruction of about 500 000 hectares of forest.
OF 1999 IN FRANCE
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
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 map atmospheric pressures recorded
during the second storm
A pine forest ravaged by the storm of
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...
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 ;
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
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
with westerly winds fast and very strong, and a warm air mass
in low layer, around 1500 meters above the ground.
Régnier helped me correct mistakes, please you to visit
Im not english speaker, some improprieties can appear
to english masters.
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you for all.