Incredible Rainstorm in Southern France
http://www.wunderground.com/blog/weatherhistorian/comment.html?entrynum=305
Torrential rainfall Tuesday through Thursday
morning (September 16-18) in the Languedoc Region of southern France has
resulted in flooding that has killed at least four people with two others still
missing. The rainfall rates during the storm were phenomenal.
An inflow of moist air from the Mediterranean
Sea resulted in a line of heavy thunderstorms that trained across the southern
French districts of Gard and Herault for almost 36 hours September 16-18. The
mountainous terrain of the region contributed to orographic enhancement of the
rainfall and some astonishing rainfall amounts were measured. A possible new
all-time 2-hour rainfall record for France of 180 mm (7.09”) was measured at
Saint-Gervais-sur-Mare (Herault District) between 10 p.m. and midnight on
September 16th, surpassing the previous record rainfall for a two-hour period
of 178.4 mm (7.02”) at Solenzara on October 26, 1979. See the Meteo France official table of records for French
two-hour time periods here. (NOTE: Short-period rainfall records for France have not been
systematically kept for very long, only since the 1970s).
Saint-Gervais-sur-Mare also measured 88 mm (3.46”) in just one hour (short of
the national record of 111.6 mm/4.39” also set at Solenzara during the event in
October 1979—see caveat about this above). Another site, Montdardier (Gard
District) picked up 273 mm (10.75”) in just five hours between 4 p.m. and 9 p.m.
(September 16th). This was the equivalent to what would normally fall in two
months this time of the year. The modern French record for any 6-hour period is
289.4 mm/11.39”, once again at Solenzara in 1979 (the Meteo France table of
record point rainfalls does not include figures for 5-hour periods).
Over the course of the entire 36-hour long storm period from Tuesady evening 8 p.m. to Thursday morning 8 a.m., a total of 468 mm (18.43”) of rainfall accumulated at Saint-Gervais-sur-Mare, the equivalent of 40% of their average annual precipitation amount. Some other totals for this same 36-hour period include:
377 mm (14.84”) at Caylar, Herault
372 mm (14.65”) at Montdardier, Gard
327 mm (12.87”) at Anduze, Gard
317 mm (12.48”) at Saint-Hippolyte du Fort, Gard
Needless to say, severe flash flooding occurred over the affected area and at least four fatalities have been reported; campers that were swept away in Lamalou-les-Bains, Herault District. Two others are missing and presumed drowned. Amazing as the storm totals were, they are not close to the French national record for any 24-hour period. The greatest modern official figure for such is 633.2 mm (24.93”) at Mont Aigoual on February 24, 1964. However, much greater amounts were estimated to have fallen during a catastrophic rain and flood event on October 17, 1940. The war had disrupted the French meteorological service at that time, so it was difficult to garner accurate information about the rain totals but 840 mm (33.07”) in 24 hours was reportedly measured at the power plant in Llau District (which borders Spain) and 1000 mm (39.37”) was estimated to have fallen in 24 hours at the nearby town of Saint-Laurent-de-Cerdans.
Over the course of the entire 36-hour long storm period from Tuesady evening 8 p.m. to Thursday morning 8 a.m., a total of 468 mm (18.43”) of rainfall accumulated at Saint-Gervais-sur-Mare, the equivalent of 40% of their average annual precipitation amount. Some other totals for this same 36-hour period include:
377 mm (14.84”) at Caylar, Herault
372 mm (14.65”) at Montdardier, Gard
327 mm (12.87”) at Anduze, Gard
317 mm (12.48”) at Saint-Hippolyte du Fort, Gard
Needless to say, severe flash flooding occurred over the affected area and at least four fatalities have been reported; campers that were swept away in Lamalou-les-Bains, Herault District. Two others are missing and presumed drowned. Amazing as the storm totals were, they are not close to the French national record for any 24-hour period. The greatest modern official figure for such is 633.2 mm (24.93”) at Mont Aigoual on February 24, 1964. However, much greater amounts were estimated to have fallen during a catastrophic rain and flood event on October 17, 1940. The war had disrupted the French meteorological service at that time, so it was difficult to garner accurate information about the rain totals but 840 mm (33.07”) in 24 hours was reportedly measured at the power plant in Llau District (which borders Spain) and 1000 mm (39.37”) was estimated to have fallen in 24 hours at the nearby town of Saint-Laurent-de-Cerdans.
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