(CNN) — In its devastating path of destruction, Hurricane Fiona has killed at least five people across the Caribbean, cut power and water service for most of Puerto Rico’s 3.1 million residents and left more than 1 million without running water in the Dominican Republic.

The storm was threatening more deadly flooding Tuesday as it slammed the Turks and Caicos islands.

Fiona, a Category 3 storm with sustained winds of 115 mph, was battering the Turks and Caicos while centered about 40 miles off Grand Turk Island around 2 p.m. ET. Its heavy rains could deliver “life-threatening flooding” through the afternoon in parts of the British territory of about 38,000 people, the Miami-based National Hurricane Center said.

Still dealing with Fiona’s ruinous path are the Dominican Republic — where the storm’s outer bands still could cause flooding after it traversed the Caribbean nation Monday — and Puerto Rico, which Fiona crossed a day earlier, causing a near blackout and leaving damage not seen there since Hurricane Maria made landfall five years ago Tuesday, officials said.

At least two people died in the severe weather in the Dominican Republic, according to Major General Juan Manuel Méndez García, director of the country’s emergency operations center. Aurielys Esther Jimenez, 18, was traveling by motorcycle when she was struck by a power pole that fell due to strong winds, the director said. She was taken to a hospital where she was later pronounced dead.

Officials there on Monday also confirmed the death of a man in Nagua, in northeastern Dominican Republic, who died after powerful winds knocked down a tree that hit him. There was also one death reported in the French territory of Guadeloupe, which Fiona hit late last week, and two in Puerto Rico.

In Puerto Rico, a 58-year-old man was swept away by a swollen river behind his home in Comerío and another man in his 30s died in a fire accident that occurred when he was trying to put gasoline in his generator while it was turned on, officials said.

In Puerto Rico, parts of which will have seen rain totals of more than 30 inches, Fiona pushed rivers to overflow and high water to collect in parts of the territory, flooding homes, streets and fields. Rushing waters wiped away a bridge, carrying its structure downstream, one video shows. Mudslides blocked some roads leading from coastal areas to the interior, a CNN crew saw.

The damage is catastrophic in the territory’s center, south and southeast regions, Puerto Rico Gov. Pedro Pierluisi said Tuesday.

A large portion of the population should have power by late Wednesday, but greater damage in the southern part of the island means restoration will take longer there, the governor said.

More than 1.17 million of the island’s roughly 1.47 million utility customers still were without power as of early Tuesday, according to estimates from PowerOutage.us, which notes updated information on restoration efforts is limited.

Fiona strengthens as it pushes north

Fiona intensified into a Category 3 storm as it moved away from the Dominican Republic’s northern coast early Tuesday.

This is the first major hurricane — Category 3 or higher — of this year’s Atlantic hurricane season.

Heavy rains around the center of Fiona will threaten the Turks and Caicos with “continued life-threatening flooding” through Tuesday afternoon, the hurricane center said.

Those islands could see 4 to 8 inches of rain Tuesday on top of what they received earlier, as well as storm surges — ocean water pushed onto land — of 5 to 8 feet, according to the hurricane center.

Hurricane conditions could be seen in Turks and Caicos into Tuesday afternoon, and tropical storm conditions — winds of at least 39 mph — were expected to spread over the southeastern Bahamas on Tuesday morning.

Strengthening is expected as Fiona turns from the Turks and Caicos. It could be a Category 4 storm — with sustained winds of 130 to 156 mph — by late Wednesday over the Atlantic. It is forecast to pass near or well west of Bermuda late Thursday or early Friday, and could still be at Category 4 when it does, forecasters say.

Over the weekend, Fiona might make landfall in eastern Canada as a hurricane. It is too early to know exactly where or how strong it might be.

Fiona leaves behind devastated Puerto Rico

Tuesday marks five years since Hurricane Maria’s catastrophic landfall in Puerto Rico and some who lived through the 2017 crisis say Fiona’s flooding destruction could be even more severe.

Juan Miguel Gonzalez, a business owner in Puerto Rico, told CNN that his neighborhood had still not finished its recovery from Maria when Fiona struck. But this time, he says, the flooding brought even more damage to their homes.

“A lot of people — more than (during) Maria — lost their houses now … lost everything in their houses because of the flooding,” Gonzalez told CNN on Monday. “Maria was tough winds. But this one, with all the rain, it just destroyed everything in the house.”

Water service also was interrupted for most, because river flooding affected filtration processes and must recede before safe treatment can resume, officials said. On Tuesday morning, about 60% of customers on the island had no running water, the territory’s aqueduct and sewer authority said.

More than 1,200 people were staying in about 70 shelters on the island Tuesday, Pierluisi said. Emergency crews battled against unrelenting rain to rescue approximately 1,000 people as of midday Monday, said Maj. Gen. José Reyes, adjutant general of the Puerto Rico National Guard.

School buildings will be inspected to make sure they are safe for students to return to class in the coming days, the governor said Tuesday.

In addition to the hundreds of Puerto Rican National Guard members aiding in rescue and recovery efforts, the White House said Monday that President Joe Biden told Pierluisi during a phone call that federal support will increase in the coming days.

“As damage assessments are conducted, the President said that number of support personnel will increase substantially,” the White House said.

New York Gov. Kathy Hochul also announced the state would send 100 state troopers to assist relief efforts in Puerto Rico. She also said teams from New York Power Authority are available to help with power restoration.

More than 1 million customers left without water service in Dominican Republic

In the Dominican Republic, where up to 20 inches of rain fell in places, emergency workers brought nearly 800 people to safety, the country’s emergency management director of operations, Juan Manuel Mendez, said Monday. At least 519 people were taking refuge in the country’s 29 shelters Monday, he said.

As of Monday afternoon, at least 1,018,564 customers across the Dominican Republic had no access to running water as 59 aqueducts were out of service and several others were only partially functioning, according to Jose Luis German Mejia, a national emergency management official.

Some in the Dominican Republic were also without electricity Monday as 10 electric circuits went offline, emergency management officials said. It’s unclear how many people are impacted by the outages.

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