Sunday, September 21, 2014

Incredible Rainstorm in Southern France

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).



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