The severe precipitation event of April 1998 in North-East Patagonia

From 21 through 24 April of 1998 an unusual precipitation system over North-East Patagonia, between latitudes 46º and 42º S, cause severe damages, particularly in the cities of Puerto Madryn and Trelew. The event, coincident with the very strong phase of the 1997-1998 El Niño warm episode, dropped 144 mm in a 24-h period and 255 for the whole 4-day period, as it was observed at the Centro Nacional Patagónico meteorological station (Puerto Madryn). It is noticeable that the annual mean precipitation for the site is 231 mm. As a consequence of the intense rainfall, natural and artificial drainage system collapsed during the morning of 24 April. Severe flooding resulted in serious damages on the mentioned cities, hitting low neighborhoods in Trelew and Puerto Madryn. Two fatalities and minor injuries were reported, hundred of persons were rescued by ground-based emergency personnel and the economical and properties loses were very significant. This work describes the regional meteorological situation associated to the above event using local observation and synoptic NCEP-NCAR Reanalysis.