Florida is facing the most dangerous storm in its history as Hurricane Matthew barrels in from the Atlantic threatening coastal cities with surging tides, torrential rain and 130 mile-an-hour winds.
After cutting a deadly swath across the Caribbean and leaving at least 264 dead in Haiti, the Category Four storm was to hit the southeastern United States early Friday.
Over the course of the day, it will scour its way up a 600-mile strip of coast from Boca Raton in Florida to just north of Charleston, South Carolina, driving seawater and heavy rain inland.
Evacuation orders were issued for areas covering at least three million residents and major cities like Jacksonville, Florida and Savannah, Georgia lay in the path of the terrible storm.
Matthew has already battered Haiti, Jamaica, Cuba, the Dominican Republic and the Bahamas and US officials were taking no chances, warning that loss of life is a virtual certainty.
"This storm is a monster," declared Florida's Governor Rick Scott. "I want everybody to survive this. We can rebuild homes. We can rebuild businesses ... We can't rebuild a life."
Matthew was churning over the ocean just off Grand Bahama Island at 8:00 pm on Thursday (0000 GMT) and heading towards Florida and South Carolina at 13 miles per hour (20 kph).
By 2:00 am on Friday, it is expected to be off Port St Lucie, threatening Florida's beaches and ports with sustained winds of up to 130 miles-per-hour and gusts of up to 160.
"And when you get the wind you will get immediate flooding, strong rip current, beach erosion. The risk of tornados," Scott warned.
"Think about this: 11 feet of possible storm surge. And on top of that, waves. So if you are close, you could have the storm surge and waves over your roof."
Highways were jammed with people streaming inland to escape the storm, forecast to be strong enough to snap trees and blow away roofs or entire houses.
As US gas stations ran dry, frantic shoppers flocked to stores for batteries, transistor radios, bread, canned goods, bottled water, ice and pet food.
Poor and vulnerable Haiti remained essentially cut in half two days after Matthew hit, with routes to the devastated south cut by flooding.
Local radio cited at least 264 dead.
At least four people -- three of them children -- were killed in Haiti's neighbor the Dominican Republic and more than 36,500 were evacuated, with 3,000 homes destroyed, flooded or damaged.
The wealthier Bahamas, which had more time to prepare, was less badly hit and there were no reports of fatalities, but there were power outages, some roads were cut and there was property damage.
- Ghost resorts -
In Myrtle Beach, South Carolina, the normally bustling resort turned into a ghost town as tourists loaded up cars, cut short vacations and fled north.
"It was packed with people here yesterday and then we came today and it was like 'Oh my God, there is nobody here,'" said Kelly Allmendinger, a 26-year-old bartender.
Officials complained a worrying number of people were not heeding evacuation orders and many communities set up storm shelters.
The fire service in St Augustine, northern Florida, issued a video message on Facebook warning that damage to the city was expected to be "catastrophic" and urging all holdouts to leave their homes.
"We as a city are evacuating," said Fire Chief Carlos Aviles. "I cannot emphasize enough: We are encouraging you to leave."
"If you are choosing to stay in St Augustine, you are choosing to do so at your own risk. There will be no public safety personnel to assist you."
The largest shelter in the quaint beach city had reached its capacity of 500 people and authorities turned frustrated residents back into the rain, pillows under their arms.
Miami International Airport canceled 90 percent of its incoming and outgoing flights on Thursday and Walt Disney World -- in Orlando, 35 miles inland -- was to stay shut on Friday.
President Barack Obama spoke with the governors of Florida, Georgia, North Carolina and South Carolina, pledging to provide them with all necessary federal resources to cope with the storm.