By Tuesday night, Hanna claimed 21 lives in Haiti, including 12 dead in the state containing the cutoff city of Gonaives, said Marie Alta Jean-Baptiste of the country's civil protection office in Port-au-Prince, the capital.
Iris Norsil, 20, managed to flee Gonaives on Haiti's western shore and told The Associated Press that people there were isolated by muddy floodwaters as evening fell, seeking refuge on rooftops as wind gusts drove horizontal sheets of rain.
"They are screaming for help," Norsil said as a U.N. aid convoy tried unsuccessfully to drive into Gonaives, now surrounded by a virtual lake of floodwaters. A team of AP journalists accompanied the convoy.
Another convoy carrying Prime Minister Michele Pierre-Louis had to abandon efforts at getting into Gonaives when one of the cars was nearly swept away, said Julian Frantz, a Haitian police officer who was providing security for the group.
Floodwaters rose rapidly outside Gonaives, where Norsil and scores of other residents who abandoned the low-lying city shivered violently in soaked clothing, nervously eying the rushing, debris-clogged waters.
"The situation is as bad as it can be," said Vadre Louis, a U.N. official in Gonaives. "The wind is ripping up trees. Houses are flooded with water. Cars can't drive on the street. You can't rescue anyone, wherever they may be."
Those who could move clutched mattresses, chairs and other belongings as they slogged through waist-high floodwaters.
Hanna's maximum sustained winds slipped to 65 mph, but the U.S. National Hurricane Center in Miami said it could regain hurricane strength and turn toward the east coast of Florida, Georgia or South Carolina in two to three days.
In Florida, Gov. Charlie Crist issued a state of emergency Tuesday to more easily mobilize emergency responders if Hanna hits the state. But forecasters warned that he entire U.S. East Coast should keep close watch.
Heavy rain from the storm's outer bands fell relentlessly in Haiti, a country still recovering from drenchings by Hurricane Gustav and Tropical Storm Fay in the past two weeks. In all, floods and mudslides from the three storms have killed more than 100 people as Haiti's deforested hills melted away in the torrential rains.
In Puerto Rico, flooding was blamed for the drowning death of a Colombian university student in a raging river. The man's Brazilian friend was missing despite a desperate search in the water.
Swirling slowly through the southern Bahamas on Tuesday, Hanna lingered over the island of Great Inagua for hours, toppling power lines but otherwise doing little damage. There were reports of heavy winds stripping shingles from roofs and knocking down trees, but no injuries, said Chrystal Glinton, a spokeswoman for the Bahamas' National Emergency Management Agency.
"Everyone is alive and well," Glinton said. "The damages have been minimal."
The same could not be said for Haiti, a country particularly vulnerable to devastating floods because of its steep terrain and hills that have been deforested for agriculture and by peasants who burn trees for charcoal.
In the fertile Artibonite Valley, rice fields were flooded and farm animals huddled on small plots of dry land. In the village of L'Ester, Wilson Elie, a local official, said rain had overwhelmed his community and he pleaded for government help.
"The people cannot live in water," Elie said.
Tropical storm winds extended out 200 miles from Hanna's center.
Meanwhile,was cruising westward across the Atlantic with top winds of 65 mph, projected to near the Bahamas by Sunday as a hurricane. Just behind it was Tropical Storm Josephine, with top winds of about 50 mph, and forecasters said it could near hurricane force by Wednesday or Thursday.
And in the Pacific, Tropical Storm Karina formed south of Mexico's Baja California Peninsula, on a path leading far out to sea. It weakened to a tropical depression Tuesday night.