Jeanne was blamed for at least six deaths in Florida. The storm had already cut a deadly path through the Caribbean, where floods in Haiti, the Dominican Republic and Puerto Rico killed some 2,000 people, Reuters reported.
Haiti suffered the heaviest toll. Two days of torrential rains caused massive flooding and mudslides in the northern region, killing at least 1,500 people. In towns such as Gonaives, an estimated 4,000 houses were destroyed and 20,000 people left homeless.
U.N. peacekeepers rushed to Gonaives to guard against looters stealing food aid while military doctors performed operations on hundreds of victims, who were injured either during the storm itself or afterward from the debris, according to the Associated Press.
"The situation remains critical," said Gen. Augusto Heleno Ribeiro Pereira, the general in charge of the U.N. force, in an interview with the official Agencia Brasil.
He said many people were suffering from diarrhea while others, many of them children, had contracted gangrene.
The director of the U.N. World Food Program's Haiti operation, Guy Gavreau, said flooding destroyed the rice and fruit harvest in the Artibonite, Haiti's most agriculturally productive region, "so now the country can't even feed itself without outside help."
WFP and CARE International have distributed 120 tons of food in the past three days -- enough to feed 48,000 families for one day, said the WFP's Anne Poulsen. Aid agencies were working around the clock to get food to storm victims, even using donkeys to reach rural areas, she said.
Having wreaked havoc in the Caribbean, Hurricane Jeanne reached Florida's shores late Saturday night. The storm followed a path similar to Hurricane Frances, which hit the state three weeks ago, and also crossed the path left by Hurricane Charley in mid-August.
Jeanne ripped roofs off buildings, toppled light poles and flooded some bridges from the mainland to the Atlantic barrier islands. Utilities estimated that more than 2.5 million homes and businesses were left without power over the weekend, according to the AP.
"The last three weeks have been horrific," said Joe Stawara, owner of a Vero Beach mobile home park where half of the 232 trailers were damaged. "And just when we start to turn the corner, this happens."
CNN reported that Jeanne has the potential to be the most expensive storm to hit the United States this year. Two catastrophe modeling firms that work for insurance companies have pegged Jeanne's total insured losses at between $4 billion and $9 billion.
If the damages equal the top end of that spectrum, Jeanne would be second only to Hurricane Andrew, which caused $20 billion in insured losses in 1992, as adjusted for inflation, according to CNN.
Hurricanes Charley, Frances and Ivan caused up to $18 billion in additional losses in Florida since mid-August.
No state has been hit by four hurricanes in one season since Texas in 1886. And the hurricane season has two more months to go.
Jeanne is expected to weaken into a tropical depression and move over the Carolinas through Tuesday.