Puerto Rico is in trouble.

A dam in northwestern Puerto Rico suffered structural damage on Friday, the governor said at a news conference, prompting evacuationsof areas nearby in the aftermath of Hurricane Maria.

“Close to 70,000 is the estimate of people that could be affected in the case of a collapse,” the governor, Ricardo Rosselló, said about the Guajataca Dam, which is operated by the Puerto Rico Electric Power Authority. “We don’t know the details. It’s time to get people out.”

A flash flood warning was previously issued by the National Weather Service for the municipalities of Isabela and Quebradillas. “This is an extremely dangerous and life-threatening situation,” the service said in an advisory.

We’ve been hearing for decades that global warming was going to hit poor people in coastal areas very hard. Now we get to watch those predictions played out before our eyes.