Hurricane Fiona roared over the Dominican Republic on Monday after knocking out power across all of Puerto Rico, causing damage the governor said was “catastrophic”.

No deaths have been reported, but authorities in the US territory said it was too early to estimate the damage from a storm that was still forecast to unleash torrential rain across Puerto Rico on Monday.

Up to 30 inches (76 centimetres) was forecast for Puerto Rico’s southern region. As much as 15 inches were projected for the eastern Dominican Republic.

“It’s important people understand that this is not over,” said Ernesto Morales, a meteorologist with the National Weather Service in San Juan.

He said flooding reached “historic levels”, with authorities evacuating or rescuing hundreds of people across the island.

“The damages that we are seeing are catastrophic,” said Governor Pedro Pierluisi.

Puerto Rico Tropical Weather
A road is blocked by a mudslide caused by Hurricane Fiona in Cayey, Puerto Rico (Stephanie Rojas/AP)

Water service was cut to more than 837,000 customers — two-thirds of the total on the island — because of turbid water at filtration plants or lack of power, officials said.

Before dawn on Monday, authorities in a boat travelled through the flooded streets of the north coastal town of Catano and used a megaphone to alert people that the pumps had collapsed and urged them to evacuate as soon as possible.

Brown water rushed through streets, into homes and even consumed a runway airport in southern Puerto Rico.

Fiona also ripped up asphalt from roads and washed away a bridge in the central mountain town of Utuado that police say was installed by the National Guard after Hurricane Maria hit in 2017 as a Category 4 storm.

The storm also ripped off the roofs of several homes, including that of Nelson Cirino in the northern coastal town of Loiza.

“I was sleeping and saw when the corrugated metal flew off,” he said as he observed how the rain drenched his belongings.

Ada Vivian Román, a 21-year-old photography student, said the storm knocked down trees and fences in her hometown of Toa Alta.

“I’m actually very anxious because it’s a really slow-moving hurricane,” she said.

She said she is also worried about whether the public transportation she relies on to get to her job at a public relations agency will be operating by the time she has to go back to the office.

“But I know that I’m privileged compared with other families who are practically losing their homes because they are under water,” she said.

Fiona was centred 35 miles (55km) south-east of Samana in the Dominican Republic, with maximum sustained winds of 90 mph (150 kph) on Monday morning, according to the US National Hurricane Centre. It was moving to the north-west at eight mph (13 kph).

Tropical storm-force winds extended out for 150 miles (240km) from the centre.

Forecasters said the storm’s was expected to emerge over the Atlantic in the afternoon and pass close to the Turks and Caicos islands on Tuesday. It could near Bermuda as a major hurricane late Thursday or on Friday.

Fiona hit Puerto Rico on the anniversary of Hurricane Hugo, which slammed into the island in 1989 as a Category 3 storm, and two days before the anniversary of 2017’s devastating Hurricane Maria — from which the territory has yet to fully recover.

That hurricane caused nearly 3,000 deaths and destroyed the power grid. Five years later, more than 3,000 homes still have only a blue tarp as a roof.

Puerto Rico Tropical Weather
A road is flooded by the rains of Hurricane Fiona in Cayey, Puerto Rico (Stephanie Rojas/AP)

Authorities announced on Monday that power had been returned to 100,000 customers on an island of 3.2 million people, but power distribution company Luma said it could take days to fully restore service.

US President Joe Biden had declared a state of emergency in the US territory as the eye of the storm approached the island’s south-west corner.

Puerto Rico’s health centres were running on generators — and some of those had failed. Health Secretary Carlos Mellado said crews rushed to repair generators at the Comprehensive Cancer Centre, where several patients had to be evacuated.

Fiona previously battered the eastern Caribbean, killing one man in the French territory of Guadeloupe when floods washed his home away, officials said.