A failing dam has sparked emergency evacuations of two towns in north-west Puerto Rico as the US territory struggled with flooding, an island-wide blackout and other dangers in Hurricane Maria's wake.
The National Weather Service in San Juan said the north-western districts of Isabela and Quebradillas, home to some 70,000 people, were being evacuated with buses because the nearby Guajataca Dam was failing.
The 345-yard dam holds back a man-made lake covering about two square miles and was built decades ago, US government records show.
All across the battered island, residents feared power could be out for weeks - or even months - and wondered how they would cope.
Some of the island's 3.4 million residents planned to head to the US to temporarily escape the desolation.
But in the short term, the soggy misery will continue: additional rain - up to 6ins - is expected through Saturday.
In San Juan, Neida Febus, 64, wandered around her neighbourhood with bowls of cooked rice, ground meat and avocado, offering food to anyone in need.
The damage was so extensive, she said, that she did not think the power would be turned back on until Christmas.
"This storm crushed us from one end of the island to the other," she said.
The death toll in Puerto Rico stood at six but is likely to rise.
At least 27 lives have been lost around the Caribbean, including at least 15 people killed on hard-hit Dominica.
Other islands reporting deaths were Haiti with three; Guadeloupe, two; and Dominican Republic, one.
By Friday afternoon, Maria was passing north east of the Turks and Caicos with winds of 125mph. A hurricane warning remained in effect for those islands as well as the southeastern Bahamas.
The storm is not expected to pose a threat to the US mainland.
Meanwhile, the loss of power left residents hunting for gas cylinders for cooking, collecting rainwater or steeling themselves mentally for the hardships to come in the tropical heat.
"You cannot live here without power," said Hector Llanos, a 78-year-old retired New York police officer who planned to leave for the US mainland to live there temporarily.
In Puerto Rico, the electric grid was in sorry shape long before Maria - and Hurricane Irma two weeks ago - struck.
The territory's €61bn debt crisis has left agencies like the state power company broke.
It abandoned most basic maintenance in recent years, leaving the island subject to regular blackouts.
The Federal Emergency Management Agency said it would open an air bridge from the mainland on Friday, with three to four military planes flying to the island every day carrying water, food, generators and temporary shelters.
Puerto Rico governor Ricardo Rossello said his administration was trying to open ports soon to receive food, water, generators, cots and other supplies.
The government has hired 56 small contractors to clear trees and put up new power lines and poles and will be sending tanker trucks to supply neighbourhoods as they run out of water.
The entire island has been declared a federal disaster zone.
Mike Hyland, senior vice president of engineering services for the American Public Power Association, a utility industry group that is sending repair crews into the Caribbean, would not speculate on how long it would take to restore power in Puerto Rico.
"Let's see what the facts tell us by the end of the weekend," he said, but acknowledged: "This is going to be a tall lift."