Hurricane Dean uprooted trees, tore down power lines and ripped the roof off a hospital in St. Lucia on Friday as it raced into the Caribbean on a track that could take it near Jamaica as a dangerously powerful storm next week, officials said.

|PIC1|On the nearby French island of Martinique, sustained winds were measured at 75 mph (120 kph) with gusts up to 105 mph (170 kph), according to France's weather service.

Dean reached the Caribbean Sea through the narrow St. Lucia Channel after a long journey across the Atlantic and threatened to become a powerful Category 4 hurricane on the five-step Saffir-Simpson scale in the area of Mexico's Yucatan Peninsula in four days.

The first hurricane of the Atlantic season lifted the roof off the pediatric wing at Victoria Hospital in St. Lucia's capital, Castries. Patients had been moved from that area and there were no immediate reports of deaths or injuries on the former British colony of 170,000 people, said Dawn French, the island's emergency management director.

"It's very gusty and it's very rainy. We had a dead calm night and now we're getting walloped," said French, reached by telephone as she hunkered down to wait out the storm.

"We seem to have a lot of debris on the roads and some downed trees and downed power lines," she said. "The all-clear hasn't been given so we really haven't been able to get out to look around yet."

By 8 a.m. EDT (1200 GMT), Dean was 50 miles (80 km) west-southwest of Martinique, the U.S. National Hurricane Center said.

It was moving to the west at a brisk 23 mph (37 kph), forecasters said, a speed that would take it well clear of the Lesser Antilles within a few hours.

"I can say it could have been a lot worse. It's not that bad," said Clinton Charlery of Charlery's Car Rental in St. Lucia.

Dean still had top sustained winds of 100 mph (160 kph), making it a Category 2 storm.

Category 3 to 5 storms, referred to collectively as "major" storms, are generally the most destructive and include infamous hurricanes like Katrina in 2005. A Category 2 hurricane is still capable of damaging houses and sending a 6- to 8-foot (1.8 metre to 2.4 metre) storm surge ashore.

The hurricane was expected to become an extremely dangerous Category 4 storm next week with winds of about 140 mph (227 kph) on a course projected to take it near Jamaica and aimed either for the Gulf of Mexico or Mexico's Yucatan Peninsula.

Dean could threaten Gulf of Mexico oil and natural gas platforms whether it goes across the Yucatan or slips directly into the gulf, where the United States gets roughly a third of its domestic crude oil and 15 percent of its natural gas.

If it crosses the Yucatan it is projected to re-emerge in the southern Gulf as a Category 2 storm and could disrupt operations in the Cantarell Complex of Mexican oil fields, which is one of the world's most productive and supplies two thirds of Mexico's crude oil output.

Tropical storm warnings were in effect for the British and U.S. Virgin Islands, Puerto Rico, Anguilla, Grenada, Saba, St. Eustatius, Montserrat, Antigua and Barbuda, St. Kitts and Nevis and St. Maarten.

Forecasters have predicted the six-month hurricane season that officially began June 1 would be more active than average with up to 16 named storms. An average year historically has 10 to 11 storms, of which six strengthen into hurricanes.