A U.S. Navy vessel, the amphibious warfare ship Iwo Jima, was steaming toward Haiti on Tuesday to provide disaster relief in case Tropical Storm Tomas strikes late in the week as forecast, possibly as a Category 2 hurricane.
The storm has already caused 14 deaths in the eastern Caribbean. Haiti issued its highest storm warning to inform people they may need to evacuate - though most have nowhere to go.
Aid groups are rushing to do what they can, but are already short of supplies after dealing with the catastrophe of the Jan. 12 quake.
Tomas would be the first big storm to strike Haiti since the earthquake killed as many as 300,000 people and forced millions from their homes. It would also be the first tropical storm or hurricane to hit since 2008, when the storms Fay, Gustav, Hanna and Ike battered Haiti in the space of a month, killing nearly 800 people and wiping out 15 percent of the economy.
Even before Tomas hits, there are shortages of 150,000 tarps as well as soap, hygiene kits, field tents, radios and oral rehydration salts for treating cholera, U.N. Humanitarian Coordinator Nigel Fisher said.
"We need emergency shelter. We need water and sanitation supplies. And we need as much of it as possible in place before Hurricane Tomas hits," Fisher said.
Warehouses are being emptied of existing stocks of rope and tarps to help people in camps, said U.N. humanitarian spokeswoman Imogen Wall.
Piles of rubble and partially collapsed buildings from the quake still fill Port-au-Prince, the capital. Reconstruction is grinding along without promised aid funds, including $1.15 billion promised by the United States.
Tomas had maximum sustained winds of 50 mph (85 kph) Tuesday and was centered about 355 miles (570 kilometers) south of Port-au-Prince. It was moving west at 10 mph (17 kph).
As a hurricane Saturday, Tomas killed at least 14 people in the eastern Caribbean nation of St. Lucia, according to Prime Minister Stephenson King, most in the hard-hit town of Soufriere.
Police Commissioner Vernon Francois warned the death toll might increase because another seven people are missing.
The storm caused more than $37 million in damages as it battered Vieux Fort, the island's second-largest town and the home of its international airport. Two main bridges were left impassable, cutting the community off from the capital, Castries.
Noelia Joseph, who lives in Soufriere, said she lost three relatives who lived with her.
"I was in the living room when a great big wind accompanied by water swept through the house, washing me into a nearby street," she said. "I tried calling to my mother but couldn't hear a thing. The top floor of the house came crashing down with my mother and two brothers still inside."
In nearby St. Vincent, Prime Minister Ralph Gonsalves described the damage as "the worst we have seen in living memory." It wrecked more than 1,200 homes and caused nearly $24 million in damages to crops, especially bananas - one of St. Vincent's top commodities. The government does not expect to export the fruit for the remainder of the year.
Hundreds of St. Vincent residents were treated in clinics for injuries, particularly in Sandy Bay on the island's northeast coast.
Haitian authorities on Tuesday issued a red alert, which warns people they may need to take precautions, even evacuate - though there is no place for most to go and little they can do to prepare.
"I didn't know about (the storm). Maybe somebody came by to say something yesterday when I was out," said Florence Ramond, a 22-year-old mother and food vendor who is living on the Petionville Club golf course in a refugee camp managed by actor Sean Penn's relief organization.
Even knowing, Ramond said, she could do nothing to secure her home, a shack made of tarp, wood and a tin door. The roof blew off in an unnamed Sept. 24 storm that ripped through the capital, killing at least five people and damaging thousands of tents.
"They always go around and tell us to tie the tarps up, but I don't have a rope," she said.
The family lost its home in the earthquake, which killed Ramond's niece. Her brother, Joel, is hospitalized with cholera in the Artibonite Valley - part of an epidemic that has killed more than 300 people and hospitalized more than 4,700.
Her infant son, Lovenson, has had bouts of diarrhea recently that she said are caused by mud flowing into their shelter. His first birthday was Monday, which was also the first day of Haiti's Voodoo festival of the dead, Fet Gede. Ramond said she doesn't have money to celebrate either.
Associated Press writers Guy Ellis in Castries, St. Lucia, and Glenford Prescott in Kingstown, St. Vincent, contributed to this article.