Hurricane Ernesto barreled toward Bermuda on Thursday after leaving hundreds of thousands of people in Puerto Rico without power or water as sweltering heat enveloped the U.S. territory, raising concerns about people’s health.

A hurricane warning was in effect for Bermuda, with Ernesto expected to pass near or over the island on Saturday.

The Category 1 storm was located about 605 miles (975 kilometers) south-southwest of Bermuda on Thursday morning. It had maximum sustained winds of 85 mph (140 kph) and was moving north at 13 mph (20 kph).

“I cannot stress enough how important it is for every resident to use this time to prepare. We have seen in the past the devastating effects of complacency,” said National Security Minister Michael Weeks.

Ernesto was forecast to become a major Category 3 hurricane on Friday and then decrease in strength as it approaches Bermuda, where it is expected to drop between four to eight inches of rain, with up to 12 inches in isolated areas.

“All of the guidance show this system as a large hurricane near Bermuda,” said the National Hurricane Center in Miami.

Meanwhile, the spinning storm on Thursday was generating southern winds in Puerto Rico, which have a heating effect as opposed to the typical cooling trade winds that blow from the east.

“We know a lot of people don’t have power,” said Ernesto Morales with the National Weather Service as he warned of extreme heat and urged people to stay hydrated.

More than 450,000 of 1.4 million customers remained in the dark more than a day after Ernesto swiped past Puerto Rico late Tuesday as a tropical storm before strengthening into a hurricane.

Hundreds of thousands also were without water as many questioned the widespread power outage given that Ernesto was only a tropical storm when it spun past the island.

“I haven't slept at all,” said Ramón Mercedes Paredes, a 41-year-old construction worker who planned to sleep outdoors on Thursday night to beat the heat. “I haven't even been able to take a shower.”

At a small park in the Santurce neighborhood of the San Juan capital, Alexander Reyna, a 32-year-old construction worker, sipped on a bright red sports drink that friends brought him as roosters crowed nearby above the slap of dominoes.

He had no water or power and planned to spend all day at the park as he lamented the lack of breeze, a slight film of sweat already forming on his forehead: “I have to come here because I cannot stand to be at home.”

The situation worried many who lived through Hurricane Maria, a powerful Category 4 storm that hit Puerto Rico in September 2017 and was blamed for at least 2,975 deaths in its sweltering aftermath. It also razed the island's power grid, which is still being rebuilt.

The National Weather Service issued a heat advisory on Thursday warning of “dangerously hot and humid conditions.”

Faustino Peguero, 50, said he was concerned about his wife, who has fibromyalgia, heart failure and other health conditions and needs electricity. He has a small generator at home, but he is running out of gasoline and cannot afford to buy more because he hasn't found work.

“It's chaos,” he said.

Officials said they don’t know when power will be fully restored as concerns grow about the health of many in Puerto Rico who cannot afford generators or solar panels on the island of 3.2 million people with a more than 40% poverty rate.

Crews were still assessing the situation, although no catastrophic damage has been identified, said Juan Saca, president of Luma Energy, a private company that operates the transmission and distribution of power in Puerto Rico.

When pressed for an estimate of when power would be restored, Alejandro González, Luma’s operations director, declined to say.

“It would be irresponsible to provide an exact date,” he said.

At least 350,000 customers across Puerto Rico also were without water given the power outages. Among them was 65-year-old Gisela Pérez, who was starting to sweat as she cooked sweet plantains, pork, chicken and spaghetti at a street-side diner. After her shift, she planned to buy gallons of water, since she was especially concerned about her two small dogs: Mini and Lazy.

“They cannot go without it,” she said. “They come first.”