Downburst in Porto Alegre

On Jan 29th (2016), Friday, Porto Alegre was hit by a devastating rainstorm that knocked down more than 4,000 trees in parks and streets causing damage to hundreds of street lamp posts and several buildings around the city. Around 100 people had minor injuries and looked for emergencies due to debris falling from buildings and small cuts caused by broken glass. Not only the fallen trees and branches, but also hundreds of damaged traffic lights brought chaos to the city’s traffic on the following days. More than 300,000 people had to face long power outages. Telephone and water distribution services were also affected.

Interestingly, no weather forecast service had predicted such powerful storm and three days later we are still wondering what exactly happened. Today (Feb 2nd), I was watching the news and the first technical explanation describing the phenomenon finally came out. It was a downburst. Not knowing anything about this kind of phenomenon, I decided to find a definition to share with you..

Definition from Wikipedia:

“A downburst is created by a column of sinking air that after hitting ground level, spreads out in all directions and is capable of producing damaging straight-line winds of over 240 km/h (150 mph), often producing damage similar to, but distinguishable from, that caused by tornadoes. This is because the physical properties of a downburst are completely different from those of a tornado. Downburst damage will radiate from a central point as the descending column spreads out when having an impact on the surface, whereas tornado damage tends towards convergent damage consistent with rotating winds.”

Last October, we had another heavy rainstorm that flooded some areas in the metropolitan area. I hope this kind of phenomenon does not become a routine here in the south of Brazil. A question remains, how much of this nature’s fury is due to human activity?

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