The eye of Hurricane Sandy made landfall on the southeastern coast of Jamaica near Kingston on Wednesday. Winds were gusting as high as 130 km/h.
Jamaicans hunkered down at home as the front edge of the storm buffeted the Caribbean island with pelting rain and howling winds early Wednesday.
The island's international airports prepared to close, cruise ships changed their itineraries and police ordered 48-hour curfews in major towns to keep people off the streets.
The storm will then spin into eastern Cuba by Wednesday evening.
Dangerous flash floods and mudslides set off by Sandy were a threat for the island of roughly 2.7 million inhabitants, Jamaica's meteorological service said.
In the hilly community of Kintyre, near the capital of Kingston, Sharon Gayle and a few of her drenched neighbours expected to lose the town's bridge over the Hope River, which washed away a section of the span just three weeks ago during a heavy downpour.
"We've gotten cut off here a whole heap of times. But with a big nasty hurricane on the way, I'm really nervous. We're trying not to show it in front of the children though," the mother of three said, huddling under a sopping white towel as she stared at the rising river.
The storm was predicted to drop as much as 25 cm of rain, especially over central and eastern parts of Jamaica. Some isolated spots could see as much as 50 cm, according to U.S. forecasters. Battering waves and a strong storm surge were also forecast.
In Cuba, authorities issued a hurricane watch for several provinces and there were intermittent rains over Haiti, where a tropical storm warning was in effect. A tropical storm watch was also posted for parts of the Bahamas, where the storm was predicted to pass on Thursday.
Although Florida was not expected to receive any direct impact from Sandy, Brian Koon, director of the U.S. state's emergency management division, said residents should remain aware of the storm and take precautions to keep themselves safe from indirect impacts including rip currents.
Late Wednesday morning, Sandy had maximum sustained winds of 130 km/hour.
Meanwhile, U.S. forecasters said Tropical Storm Tony had formed over the open Atlantic, but posed no threat to land. The storm had maximum sustained winds of about 65 km/h. Its centre was 2,425 km west-southwest of the Azores.
With files from the Canadian Press