Severe Events Affecting Rio Grande do Sul in 2009

Abstract

In this study was analyzed the seasonal distribution of the number of days with severe events occurred in Rio Grande do Sul in 2009 (SE_RS), the regions affected by these SE_RS, the impact of the SERS which has presented the highest daily frequency, and has reached the greatest number of municipalities. Data of SERS daily occurrence and municipalities affected by these SE_RS (MA_SE) from 01/01/2009 to 12/31/2009, obtained from CEDCRS (Coordenadoria Estadual de Defesa Civil do Rio Grande do Sul) database, were used. The results showed that: there were occurrences of SE_RS in ~26% of the days in 2009; ~61% of the Rio Grande do Sul municipalities were hit by SE in 2009, and the worst-hit region was the Northwestern Rio-Grandense. We also observed that the higher occurrence of SE_RS and MA_SE in OND (Oct., Nov., Dec.) was due to seasonal atmospheric conditions characteristics of the region associated to the role of a moderated El Niño. In 2009, the windstorm was the SE that showed the highest daily frequency; reached the highest number of municipalities; generated emergency situation in ~94% of occurrences; reached more than 100 thousand people, and caused agriculture damage in ~ 22% of the municipalities affected. In addition, the quarter and the Rio Grande do Sul region most affected by windstorm in 2009 were OND and Northwest Rio-Grandense, respectively.