The death toll from Tropical Storm Noel in the Caribbean has risen to more than 100 - making it the deadliest storm of the Atlantic region this year.
Sixty-six people have now died in the Dominican Republic, where over 62,000 residents have fled their homes, and 40 are confirmed dead in Haiti.
Forecasters say Noel is accelerating through the Bahamas and could grow into an extra-tropical cyclone in 24 hours.
Hurricane Felix killed 101 people in Nicaragua and Honduras in September.
At 1700 local time (2100 GMT) the centre of Noel was 40 miles (65km) north-north-east of the Bahamas and about 205 miles (330km) east-south-east of Florida.
Packing sustained winds of up to 100km/h (62 mph), the storm is expected to cause coastal flooding as it passes Florida, the US National Hurricane Center said.
The islands of the north-western Bahamas have been placed under hurricane watch amid fears the storm will strengthen.
The Bahamas has grounded flights and residents are boarding up their homes and stocking up on basic goods.
Rescuers have been struggling to reach cut-off communities on Hispaniola - the island shared by the Dominican Republic and Haiti.
A 30-day state of emergency has been declared in the Dominican Republic, where dozens of people are missing after chest-high flood waters surged across swathes of the country.
President Leonel Fernandez has launched an international appeal for loans of $200m (£96m) to rebuild ravaged roads, collapsed bridges and a smashed electrical network.
Helicopters and boats are trying to reach communities that have been isolated after three days of heavy rainfall.
The villages of Piedra Blanca and Villa Altagracia were swept away when swollen rivers overflowed.
Bienvenido Castillo, who was rescued by boat, lost his whole family in the storm.
"I've been here for 20 years and this has just finished me off. It took 60 chickens, 26 pigs - and my family," he said.
In Haiti, most of the bodies have been found in and around the capital, Port-au-Prince.
Rescuers fear the death toll could climb once they reach remote rural towns.
Haiti is especially vulnerable to flash floods and mudslides because most of its trees have been felled to make charcoal.
One person was also killed in Jamaica.
Noel has also wreaked havoc across provinces in central and eastern Cuba, but no deaths have been reported.
At least 2,000 homes have been damaged, thousands of tons of crops have been obliterated and 24,000 people have been evacuated, according to reports.