Petropolis, Brazil was devastated this week by landslides, with over a hundred dead.

Petropolis is a mountain city in the Serra do Mar range in Brazil, with a population of over 300,000 people 40 miles upriver from Rio de Janeiro. And while landslides are an inevitability in any mountain region, the region has seen slides kill over 1,500 people since 1981. And researchers believe that most or all of those deaths were preventable.

Rapid city growth with poor planning and no subsidized housing is part of the problem – Petropolis’s slums have expanded rapidly in the last 40 years, most of that expansion entirely unregulated. It has deforested the hillsides surrounding the city, removing erosion control and making the landscape particularly vulnerable to slides. Those same slums aren’t built to any sort of code, which makes many of them deadly traps in the face of any natural disaster.

The other part of the problem, as in most of the world, is climate change. The area is already used to heavy rains, with up to 18 inches a month during the Southern summer, but recent years have seen Petropolis receive two or three times that. Climatologists, geologists, and civil engineers have warned Petropolis officials of the risks for years and recommended relocation efforts for the citizens in most danger approximately 20,000 households, but nothing has yet been done.

On Monday, the day before this recent wave of landslides, a rainstorm dumped 10 inches of rain on the city and surrounding hills in only three hours, the most rain seen in a single day since 1932. Warning alarms were sounded through the city, but no evacuations were alerted. Tuesday morning, eight landslides took out entire neighborhoods, tearing through the closely-packed districts of below-code housing. 136 people have been confirmed killed, over 200 are still missing, and both of these numbers will certainly rise as more information is gathered.

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