Some 70,000 people were ordered to evacuate their homes after a rain-swollen dam in Puerto Rico failed in the latest disaster caused by Hurricane Maria.
With the death toll from the storm at 33 across the Caribbean, the National Weather Service office in San Juan yesterday issued a flash flood warning for people living along the Guajataca River in the northwest of the island and said the 1920s dam was about to collapsing altogether.
"All Areas surrounding the Guajataca River should evacuate NOW. Their lives are in DANGER!," the service said in a tweet. Flooding has already begun downstream, it said.
Shortly thereafter, Governor Ricardo Rossello issued an order for some 70,000 people living in the area to get out.
Puerto Rico was already battling dangerous floods after Hurricane Maria ravaged the island early Wednesday. Rescuers raced against time to reach trapped residents.
Rossello has called Maria the most devastating storm in a century after it destroyed the US territory's electricity and telecommunications infrastructure.
Rossello told CNN the island is lacking communications and the preliminary assessment at this point is 13 fatalities.
"Right now our efforts are to make sure we have everybody safe, that we can rescue people. Our efforts have already produced almost 700 rescues so we're clearly focused on that."
The National Hurricane Center said some areas in Puerto Rico could see 40 inches (more than a meter) of rain from Maria, and Rossello warned of dangerous mudslides brought on by the deluge.
"We have a lot of flooding, we have reports of complete devastation of vulnerable housing. Of course it's still raining over here."
Maria has been blamed for at least 33 deaths, including 15 in Dominica, three in Haiti and two in Guadeloupe.
After lamenting that Puerto Rico had been "absolutely obliterated" by Maria, US President Donald Trump spoke with Governor Rossello Thursday night and promised to speed up relief efforts.
Although the southeast coast suffered the worst damage, no part of the island escaped the storm's wrath, including the capital San Juan where there was widespread flooding.
The city's mayor, Carmen Yulin Cruz, said the biggest need was getting emergency medication and supplies to vulnerable people who are stranded in their homes.
"Yesterday we were canvassing and we found elderly people that don't have blood pressure medicine, food," she said.
"I got an SOS from (an elderly home) and it was a text like from a horror movie. It said if anybody can hear us, please, we are stuck here and we can't get out and we have no power and we have very little water left. We got there just in time.