SAN JUAN, Puerto Rico (Reuters) - Hurricane Maria, the second major storm to ravage the Caribbean in a month, skirted past the Turks and Caicos Islands on Friday, leaving devastation in its wake that included fresh flooding on Puerto Rico two days after pummeling the U.S. island territory.

Maria, which ranked as the most powerful hurricane to strike Puerto Rico in nearly a century, has killed at least six people there and claimed 19 lives on several other Caribbean islands, according to government officials and local news media accounts.

But even as Puerto Ricans struggled without electricity to clean up and dig out from tangles of rubble, uprooted trees and fallen power lines, another potential disaster was unfolding in northwestern corner of the island, where a dam was on the verge of collapse.

The U.S. National Weather Service warned in a series of bulletins that the dam on the rain-engorged Guajataca River, was failing, causing flash flooding in the area and prompting an evacuation of communities below the reservoir by way of buses.

Roughly 70,000 people live in the area downstream from the earthen dam that was under evacuation, the island’s governor, Ricardo Rossello, said in a late-afternoon news conference.

Christina Villalba, an official for the island’s emergency management agency, said there was little doubt the dam would give way.

“It could be tonight, it could be tomorrow, it could be in the next few days, but it’s very likely it will be soon,” she said, adding that authorities were aiming to complete evacuations Friday night.

Maria struck Puerto Rico as a Category 4 storm on the five-step Saffir-Simpson scale and cut a path of destruction through the center of the island on Wednesday, ripping roofs from buildings and triggering widespread flooding. Torrential downpours from the storm sent several rivers to record levels.

Officials in Puerto Rico, an island of 3.4 million inhabitants, confirmed six storm-related fatalities: three from landslides in Utuado, in the island’s mountainous center; two from drowning in Toa Baja, west of San Juan, and a person near San Juan who was struck by a piece of wind-blown lumber.

Earlier news media reports had put the island’s death toll as high as 15.

“We know of other potential fatalities through unofficial channels that we haven’t been able to confirm,” said Hector Pesquera, the government’s secretary of public safety.

In and around San Juan, the capital, people worked to clear debris from the streets on Friday, some working with machetes, while others began to reopen businesses, though they wondered how long they could operate without power and limited inventory.

“There’s no water, no power, nothing,” said Rogelio Jimenez, a 34-year-old pizzeria worker.

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Motorists lined up for hours outside the few gasoline stations that were open. “I’ve been here for three and a bit hours,” said Angel Serra, sitting in a blocks-long line hoping to fill up his tank.

Long lines also formed at the handful of automated teller machines that appeared to be working in the region.

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DAMAGE ESTIMATED AT $45 BLN

Puerto Rico was already facing the largest municipal debt crisis in U.S. history. A team of judges overseeing its bankruptcy has advised involved parties to put legal proceedings on hold indefinitely as the island recovers, said a source familiar with the proceedings.

The storm was expected to tally $45 billion in damage and lost economic activity across the Caribbean, with at least $30 billion of that in Puerto Rico, said Chuck Watson, a disaster modeler at Enki Research in Savannah, Georgia.

Elsewhere in the Caribbean, 14 deaths were reported on Dominica, an island nation of 71,000 inhabitants. Two people were killed in the French territory of Guadeloupe and one in the U.S. Virgin Islands. Two people died when the storm roared past the Dominican Republic on Thursday, according to local media outlet El Jaya.

Maria churned past Turks and Caicos and was 295 miles (480 km) east of the Bahamas by 8 p.m. EDT (midnight GMT) on Friday, the NHC said. It was packing sustained winds of up to 125 miles per hour (205 km per hour), making it a Category 3 hurricane, but was expected to gradually weaken over the next two days as it turned more sharply to the north.

Officials on Turks and Caicos, a British overseas territory, had ordered residents to remain indoors and businesses to close on Friday as the hurricane neared, bringing a storm surge of as much as 12 feet (3.7 meters) above normal tide levels. But hurricane warnings were later canceled as Maria passed.

Storm swells driven by Maria were expected to reach the southeastern coast of the U.S mainland on Friday, the NHC said, adding that it was too soon to determine what, if any, other direct effects it would have.

In the Dominican Republic, Maria damaged nearly 3,000 homes and sent more than 9,300 to shelters, local emergency response agencies reported.

Maria passed close by the U.S. Virgin Island of St. Croix, home to about 55,000 people, early Wednesday, knocking out electricity and most mobile phone service.

Maria hit about two weeks after Hurricane Irma pounded two other U.S. Virgin Islands: St. Thomas and St. John. The islands’ governor, Kenneth Mapp, said it was possible that St. Thomas and St. Croix might reopen to some cruise liner traffic in a month.

Irma, one of the most powerful Atlantic storms on record, killed more than 80 people in the Caribbean and the United States. It followed Harvey, which also killed more than 80 people when it struck Texas in late August and caused flooding in Houston.

More than two months remain in the Atlantic hurricane season, which runs from June 1 to Nov. 30, although the busiest period is generally from mid-August to mid-October.