PORT-AU-PRINCE, Haiti (NBC) -- The most powerful Atlantic tropical storm in almost a decade made landfall early Tuesday in Haiti, where it could deliver yet another devastating humanitarian disaster to the poorest nation in the Western Hemisphere.
As of 11 a.m. ET, Hurricane Matthew was a Category 4 storm with maximum sustained winds of 145 mph, according to the National Hurricane Center. It hit Haiti just after 7 a.m., the Weather Channel reported.
Weather Channel meteorologist Kevin Roth said that Matthew could dump up to 20 inches of rain on the Haiti's lower elevations, and up to 40 inches in the mountains.
As the storm approached Tuesday, the rain and wind left many of the people in Haiti's southern town of Les Cayes without electricity and hunkering down in homes with roofs that were quickly deteriorating.
Chris Bessey, country representative at Catholic Relief Services in Port-au-Prince, told NBC News he was hearing reports of downed trees and significant flooding in the streets of the country's southwestern coastal towns.
Haiti's civil protection agency earlier reported one death — a fisherman who drowned in rough water churned up by the storm. That raised Matthew's death toll to at least three. One man died in Colombia and a teen was killed in St. Vincent and the Grenadines as the storm moved through the Caribbean.
Government officials and aid workers had set up a number of shelters in every major city and had encouraged residents to in low-lying areas to make their way to one of them, Bessey said. But many refused to leave their properties.
"They're hunkered down," said Bessey. "They're right in the middle of it."Chantal Elie, a political analyst who huddled with her husband and two kids in their home, about 8 miles south of Port-au-Prince, said "trees are falling like crazy."
Elie told NBC News she had left her house briefly to survey the damage, but the winds were too strong to stay outside.
"My daughter is very worried. She told me, 'Mom, I can't die right now because I have to finish school. I'm too young,'" Elie said, adding that she was resolved to stay calm in order to comfort the kids.
The extent of the storm's damage was unknown, but officials anticipated finding chaos. "It's much too early to know how bad things are but we do know there are a lot of houses that have been destroyed or damaged in the south," Marie Alta Jean-Baptiste, the director of the country's Civil Protection Agency, told The Associated Press.
The storm is later expected to move on to Cuba, which forecasters said can expect between 8 and 12 inches of rain for most areas, with as much as 20 inches in isolated areas.
The National Hurricane Center warned that storm surges of up to 11 feet were possible on Cuba's southern coast.
A hurricane warning was also for issued for parts of the Bahamas early Tuesday. A storm surge of 10 to 15 feet was predicted there.
Matthew is the most powerful Atlantic storm since 2007 and could make landfall in the U.S. later this week.
While its potential impact on the U.S. remained unclear, NBC News meteorologist Bill Karins suggested that the storm's path could be reminiscent of Hurricane Floyd in 1999 — which required the evacuation of 2.6 million people across five states.
As of Tuesday morning, Karins expected the storm could be a "major hurricane" from Florida all the way to North Carolina, though he noted the projected impact might fluctuate.
"Unfortunately, the models continue to show a westward trend," Roth said early Tuesday. "That means the potential for a landfall or some impacts in the U.S. is increasing."
The area most at risk of being affected by Matthew is the southeastern coast, anywhere from Florida up through North Carolina. Both Florida Gov. Rick Scott and North Carolina Gov. Pat McCrory activated states of emergency on Monday, covering 66 counties in North Carolina and all counties in Florida."Right now, the projected path is a little off the coast, but it can change at a moment's notice," Scott said at a news conference Monday. "When that happens, we're not going to have a lot of time to get ready."
Karins warned that Tuesday was a "very important preparation day for all of the southeast coast."
"The possibility exists for mandatory evacuations starting as early as late this evening in South Florida and definitely Wednesday for southern half of Florida on the East Coast," Karins added.
Karins predicted that Matthew would remain a Category 3 or 4 hurricane by the time it neared Florida on Thursday and likely would be a Category 2 or 3 if it reaches Georgia and North Carolina on Friday.When hurricanes are particularly deadly or destructive, the names are retired. Meteorologists expect this to be the last hurricane named Matthew.
"Certainly, the way this one is going, even if it doesn't hit the U.S. directly … I would say this is the last Matthew," Roth said.