Hundreds of thousands of people are fleeing the Atlantic coast of Florida ahead of the imminent arrival of Hurricane Matthew.
Matthew, the first major hurricane threatening a direct hit on the United States in more than 10 years, has lashed Florida on Friday with heavy rains and winds after killing at least 339 people in Haiti on its destructive march north through the Caribbean.
Although the hurricane was downgraded to a Category 3 storm as it approached the US mainland, winds gusts of up to 133km/h and heavy downpours are being reported across coastal communities in Florida, the National Hurricane Center (NHC) said.
"We are just bracing and the winds are picking up," Daytona Beach Mayor Derrick Henry told CNN early today.
"A great number of our residents have taken heed to our warnings and we are certainly concerned about those that have not."
More than 200,000 people are without power in Florida and it is expected that a storm surge could reach up to 3.35m in some places.
More than 3000 flights have been cancelled and Amtrak trains between Miami and New York have been suspended.
At 7pm (NZ time) Matthew was about 125 km southeast of Florida's Cape Canaveral, the NHC said. It was heading northwest at about 22 km/h and was expected to continue on this track for the next few hours.
The center said the storm is expected to gradually weaken during the next 48 hours.
More than 140,000 Florida households were without power, according to Governor Rick Scott.
Hurricane Matthew brings with it extremely dangerous 195 km/h winds, and has pounded the northwestern part of the Bahamas en route to Florida's Atlantic coast, the US National Hurricane Center said.
Matthew could plow inland or tear along the Atlantic coast through Friday night, the Miami-based center said.
Few storms with winds as powerful as Matthew's have struck Florida, and the NHC has warned of "potentially disastrous impacts."
The US National Weather Service said the storm could be the most powerful to strike northeast Florida in 118 years.
Hurricane conditions were expected in parts of Florida on Friday and a dangerous storm surge was expected to reach up to 3.35m along the Florida coast, Ed Rappaport, deputy director of the Miami-based NHC, said on CNN.
"What we know is that most of the lives lost in hurricanes is due to storm surge," he said.
It was too soon to predict where Matthew might do the most damage in the United States, but the NHC's hurricane warning extended up the Atlantic coast from southern Florida through Georgia and into South Carolina.
More than 12 million people in the United States were under hurricane watches and warnings, according to the Weather Channel.
The last major hurricane, classified as a storm bearing sustained winds of more than 177 km/h, to make landfall on U.S. shores was Hurricane Wilma in 2005.
'As serious as it gets'
Roads in Florida, Georgia and North and South Carolina were jammed, and gas stations and food stores ran out of supplies as the storm approached early on Thursday.
Governer Scott warned there could be "catastrophic" damage if Matthew slammed directly into the state and urged some 1.5 million people there to evacuate.
"If you're reluctant to evacuate, just think about all the people ... already killed," Scott said at a news conference. "Time is running out. This is clearly either going to have a direct hit or come right along the coast."
Scott, who activated several thousand National Guard troops to help deal with the storm, warned that millions of people were likely to be left without power.
Florida, Georgia and South Carolina opened shelters for evacuees. As of Thursday morning, more than 3,000 people were being housed in 60 shelters in Florida, Scott said.
Those three states as well as North Carolina declared states of emergency, empowering their governors to mobilize the National Guard.
President Barack Obama called the governors of the four states on Thursday to discuss preparations for the storm. He declared a state of emergency in Florida and South Carolina, a move that authorized federal agencies to coordinate disaster relief efforts. Late Thursday, Obama declared an emergency in Georgia and ordered federal aid to the state.
"Hurricane Matthew is as serious as it gets. Listen to local officials, prepare, take care of each other," Obama warned people in the path of the storm in a posting on Twitter.
Hundreds of passenger flights were canceled in south Florida, and cancellations were expected to spread north in coming days along the storm's path, airlines including American Airlines, Delta Airlines and United Airlines said.
-Reuters / BBC