Hurricane Matthew has slammed into Haiti's southwestern tip with howling wind, knocking down trees and tearing off roofs while inundating neighbourhoods.
By nightfall on Tuesday (midday Wednesday NZ Time), at least 11 deaths had been blamed on the powerful storm during its week-long march across the Caribbean.
But with a key bridge washed out, impassable roads and phone communication cut off with Haiti's hardest-hit area, there was no way to know how many people might be dead or injured.
The storm whipped at Cuba's sparsely populated eastern tip Tuesday night as it headed for a two-day run up the length of the Bahamas that would take it near the US coast.
Hours after Matthew made landfall on Haiti's now-marooned southwestern peninsula, government leaders said they could not fully gauge the impact.
"What we know is that many, many houses have been damaged. Some lost rooftops and they'll have to be replaced while others were totally destroyed," Interior Minister Francois Anick Joseph said.
At least five deaths were blamed on the storm in Haiti, including a 26-year-old man who drowned trying to rescue a child who fell into a rushing river, authorities said. The child was saved.
The mayor in flooded Petit Goave reported two people died there, including a woman who was killed by a falling electrical pole.
Four deaths were recorded in the neighbouring Dominican Republic and one each in Colombia and in St Vincent and the Grenadines.
Forecasters said Matthew could hit Florida by Thursday night and push its way up the east coast at the weekend.
The forecast triggered a rush by Americans to stock up on food, petrol and other emergency supplies.
The dangerous category-four storm - at one point the most powerful hurricane in the region in nearly a decade - blew ashore around dawn in the poorest country in the western hemisphere, hitting a corner of Haiti where many people live in shacks of wood or concrete blocks.
Haitian authorities had tried to move people from the most vulnerable areas before the storm, but many were reluctant to leave, and some sought shelter only after the worst was already upon them.
Matthew was expected to drop up to 1m of rain in isolated places of Haiti, along with 3m of storm surge and battering waves.
"They are getting everything a major hurricane can throw at them," said Dennis Feltgen, a meteorologist with the US National Hurricane Center in Miami.
As of 8pm (1pm Wednesday NZ Time) the storm's centre was making landfall near Cuba's sparsely populated eastern tip, with winds of 220km/h.
By Tuesday evening, 6m waves began pounding the seafront promenade in the Cuban town of Baracoa and wind tore ceramic tiles off the corners of some roofs.
In the US, Florida Governor Rick Scott urged coastal residents to prepare for the possibility of a direct hit and line up three days' worth of food, water and medicine.
The Red Cross put out a call for volunteers in South Carolina, and the White House said relief supplies were being moved to emergency staging areas in the southeast.