The resort archipelago of Bermuda geared Friday for a hit from Hurricane Gonzalo, forecast to produce flooding, strong winds and a life-threatening storm surge.

As of early Friday, Gonzalo's winds were whirling at 130 miles (215 kilometers) per hour, with even stronger gusts.

On Thursday it had gained strength, rising a notch to four on the five-point Saffir-Simpson scale, the US National Hurricane Center said.

It was expected to pass Friday near Bermuda, which could see flooding along the coast. Gonzalo, which has already killed one person in the Caribbean, triggered a hurricane warning for the British overseas territory.

"A dangerous and life-threatening storm surge is expected to produce significant coastal flooding in Bermuda," the center said in an update at 0900 GMT.

"The surge will be accompanied by large and destructive waves."

The archipelago's premier Michael Dunkley said government offices and schools would be closed Friday in the grouping of islands that is home to about 60,000 people.

"We should expect at least 24 hours of storm force winds," Dunkley said in a statement Thursday.

"During this time I want to encourage everyone to stay inside, and particularly off the roads."

The international airport was expected to shutter from late Thursday until at least Saturday.

At 0900 GMT, the storm was located about 240 miles (385 kilometers) south-southwest of Bermuda. It was moving north at 15 miles (24 kilometers) per hour, according to the Miami-based NHC.

The eye of the storm will be near Bermuda Friday afternoon and night, it added.

Forecasters stressed that major hurricanes like Gonzalo tend to fluctuate in strength.

The storm could weaken slowly Friday but Gonzalo is on track to be a "dangerous hurricane" when it moves near Bermuda, the NHC said.

The NHC noted that elevated and hilly terrain could experience especially strong winds, since wind speeds atop and on the windward sides can often be up to 30 percent stronger than at the surface.

Gonzalo's only known victim so far was an octogenarian sailor killed in the Dutch territory of St Maarten.

Three people were reported missing in the adjacent French territory of St Martin and on the island of St Barthelemy after the storm passed, and French authorities expressed concern about four other people they were trying to contact.

The storm caused damage to property on both islands, which were battered by strong winds and heavy rains.

Up to six inches (15 centimeters) of rain were expected over Bermuda.

Large swells triggered by Gonzalo were already affecting parts of the Virgin Islands, the northern coast of Puerto Rico and the Dominican Republic, as well as portions of the Bahamas.

Gonzalo is the seventh storm of the Atlantic season -- which stretches from June to November -- and the third hurricane to slam the Caribbean this year.

Hurricane Cristobal left at least four people dead in late August when it thrashed the Bahamas, Turks and Caicos Islands and Dominican Republic with heavy rains causing serious flooding.

The NHC predicted that storm activity will be lower than average this year.