SAN JUAN, Puerto Rico — Hurricane Dorian moved out over open waters early Thursday after doing limited damage in Puerto Rico and the Virgin Islands, though forecasters warned it was gaining strength and probably would grow into a dangerous storm while heading toward the northern Bahamas and Florida’s east coast.

The U.S. National Hurricane Center said Dorian was expected to strengthen into a dangerous Category 3 hurricane as it stayed well to the east of the southeastern and central Bahamas over the next two days. The forecast called for the storm to pass near or over the northern Bahamas on Saturday and close in on Florida by Sunday afternoon.

The storm was a Category 1 hurricane Wednesday when it swirled through the islands of the northeastern Caribbean, causing power outages and flooding in places but doing no major damage.

“We’re happy because there are no damages to report,” said William Solis, the mayor of the small Puerto Rican island of Culebra. He said only one community lost power.

Dorian caused an islandwide blackout in St. Thomas and St. John in the U.S. Virgin Islands, and scattered power outages in St. Croix, government spokesman Richard Motta said. In addition, the storm downed trees and at least one electric pole in St. Thomas, he said, adding that there were no reports of major flooding.

“We are grateful that it wasn’t a stronger storm,” he said.

There were no reports of serious damage in the British Virgin Islands, where Gov. Augustus Jaspert said crews were already clearing roads and inspecting infrastructure by late Wednesday afternoon.

Late Wednesday, Dorian was centered about 90 miles (145 kilometers) north of San Juan. The U.S. National Hurricane Center said its maximum sustained winds had increased to 85 mph (140 kph) as the storm moved northwest at 13 mph (20 kph).

Dennis Feltgen, a Hurricane Center meteorologist in Miami, said earlier that Dorian would strengthen and could hit anywhere from South Florida to South Carolina.

“This will be a large storm approaching the Southeast,” he said.

People in Florida were starting to get ready for a possible Labor Day weekend strike, with county governments along Florida’s east-central coast distributing sandbags and many residents rushing to warehouse retailers to load up on water, canned food and emergency supplies.

“All Floridians on the East Coast should have 7 days of supplies, prepare their homes & follow the track closely,” Gov. Ron DeSantis said in a tweet. Later Wednesday, he declared a state of emergency for the counties in the storm’s path.

Puerto Rico seemed to be spared any heavy wind and rain, a huge relief to many on an island where blue tarps still cover some 30,000 homes nearly two years after Hurricane Maria. The island’s 3.2 million inhabitants also depend on an unstable power grid that remains prone to outages since it was destroyed by Maria, a Category 4 storm.

Ramonita Torres, a thin, stooped, 74-year-old woman who lives by herself in the impoverished, flood-prone neighborhood of Las Monjas in the capital of San Juan, was still trying to rebuild the home she nearly lost after Maria but was not able to secure the pieces of zinc that now serve as her roof.

“There’s no money for that,” she said, shaking her head.

Several hundred customers were without power across Puerto Rico, said Angel Figueroa, president of a union that represents power workers.

Police said an 80-year-old man in the northern town of Bayamon died Wednesday after he fell trying to climb up to his roof to clear it of debris ahead of the storm.

Before the storm, President Donald Trump sent a tweet assuring islanders that “FEMA and all others are ready, and will do a great job.”

He then added a jab at Puerto Rican officials who have accused his administration of a slow and inadequate response to Hurricane Maria: “When they do, let them know it, and give them a big Thank You — Not like last time. That includes from the incompetent Mayor of San Juan!”

The mayor, Carmen Yulin Cruz, tweeted that Trump needs to “calm down get out of the way and make way for those of us who are actually doing the work on the ground,” adding that maybe he “will understand this time around THIS IS NOT ABOUT HIM; THIS IS NOT ABOUT POLITICS; THIS IS ABOUT SAVING LIVES.”

By DANICA COTO Associated Press

Associated Press writers Adriana Gomez Licon in Miami and Mike Schneider in Orlando, Florida, contributed to this report.