I read that it could be an electrical problem — a short or spark of some sort — or a hot air balloon. Yes, hot air balloon. Evidently it’s a Brazilian tradition to launch small homemade hot air balloons containing candles or some other compact heat-generating flame, and these same balloons often land on rooftops, causing many fires year in and year out.
These days, I’m not surprised. The marvel is that it diesn’t happen more often.
Time for metal roofs?