Tropical Storm Noel lashed the Dominican Republic with heavy rains, causing flooding and mudslides that killed at least 20 people and left another 20 missing, officials said.
Noel was expected to dump up to 20 inches (50 centimeters) of rain on the Dominican Republic and Haiti, which share the island of Hispaniola, as it heads northwest toward the Bahamas.
The storm was expected to veer away from the United States, but forecasters said a tropical storm watch, which means that tropical storm conditions are possible within 36 hours, may be issued for southeast Florida early Tuesday.
The spinning tropical storm had been forecast to hit Haiti hardest but veered toward the Dominican Republic on Monday, apparently catching residents offguard.
"We didn't know that it was going to be like this, it took us by surprise," said Guarionex Rosado as he left his home in La Cienaga, one of Santo Domingo's most affected neighborhoods.
Noel temporarily knocked out the Dominican Republic's entire power system early Monday, plunging 9.4 million people into the dark for about two hours, said Radhames Segura, vice president of the state-owned electric company.
Some buildings tumbled down hillsides near the Dominican capital and a cell phone tower slammed to the ground in the southwestern province of Barahona. At least 10 people went missing when the Maimon River overflowed its banks and a sent a torrent of muddy water rushing through the town of Piedra Blanca.
Manuel Antonio Luna Paulino, president of the Dominican Republic's National Emergency Commission, said at least 20 people had died and another 20 were reported missing.
Three of those killed died when they were swept up by a fast-moving river in San Jose de Ocoa, southwest of the capital. Three more - a couple and their child - were killed in a mudslide in the port city of Haina, officials said.
International aid workers believe the death toll is certain to rise as reports come in from remote areas of the Dominican Republic and Haiti.
"I think this has taken some officials by surprise. The storm was predicted to go more toward Haiti," said Holly Inuretta, a regional adviser for U.S.-based Catholic Relief Services.
Haitian Prime Minister Jacques Edouard Alexis said there were no immediate reports of casualties in his country, but he urged people to seek shelter. "It's moving very slowly and dropping a lot of rain," he said
Haiti is prone to deadly flooding because of its steep mountains and hills deforested by people who cut down the trees to make charcoal. Floods earlier this month killed at least 37 and sent more than 4,000 people to shelters.
Late Monday, the U.S. National Hurricane Center said heavy rains continued to pound Hispaniola and rain had started falling on parts of the southeastern Bahamas. Noel had winds of up to 50 mph (85 kph).
At 11 p.m. EDT (0400 GMT), Noel's center was about 305 miles (490 kilometers) south-southeast of Nassau, Bahamas, forecasters said. It was heading northwest at roughly 13 mph (20 kph). At that pace, the storm should move between the central Bahamas and the northern coast of Cuba on late Monday or Tuesday.
A tropical storm warning was discontinued for Haiti. A tropical storm warning was in effect for the central and southeastern Bahamas, as well as the Cuban provinces of Ciego de Avila, Camaguey, Las Tunas, Holguin and Guantanamo, according to the hurricane center.