The tragic fire event of June 17, 2017 in Portugal: the meteorological perspective

Like Mediterranean Europe, Portugal is prone to the occurrence of large and destructive wildfires that have serious impacts at the socio-economic and ecological levels. A tragic example is the episode of June 17, 2017 at Pedrógão Grande-Góis, with an official death toll of 64 people, almost 500 buildings destroyed and a continuous patch of more than 42 thousand hectares burned in one week. Climate and meteorology play a determinant role in the onset and spreading of large wildfire events in the Mediterranean basin. Two main kinds of atmospheric mechanisms may be identified. At the regional and the seasonal levels, a wetter-than usual winter followed by a warmer and drier than average spring makes the landscape prone to the occurrence of large fires. At the local and the daily scales, extreme weather conditions favor the ignition and spread of wildfires. This dual role may be assessed by means of indices of meteorological fire danger like FWI and DSR. We show that the severity of the 2017 fire season was correctly anticipated by means of a statistical model based on cumulated values of DSR starting on April 1. We then show that extreme danger of fire on June 17 was correctly forecasted for the area of Pedrógão Grande-Góis, based on values of estimated probability of exceedance of daily released energy by active fires. These two statistical approaches are on the basis of a website developed at Instituto Dom Luiz (IDL) at the Faculty of Sciences of the University of Lisbon. With more than 400 registered users, the website relies on products disseminated by the Land Surface Analysis Satellite Application Facility (LSA SAF), coordinated by IPMA, the Portuguese Weather Service.