(ABC NEWS) -- Hurricane Matthew battered the Florida coast today with powerful winds, potentially devastating storm surges and torrential rain, leaving over 1 million people without power as officials made last-minute appeals for any remaining holdouts to get out of harm's way.
Three people have died in Florida from the storm.
Officials in St. Lucie County, Florida, said two people died overnight when emergency officials could not get to them because of the storm's strong winds.
One victim, a woman in her late 50s, died from cardiac arrest, according to St. Lucie fire department officials. Crews could not safely respond to her location and the woman died by the time crews arrived, officials said.
Later in the night in St. Lucie County, there was a report of an unconscious 82-year-old man breathing with difficulty. "When it was deemed safe for emergency vehicles to travel it was reported to first responders that the patient had been taken to the hospital," according to officials. The man was later declared dead.
The third fatality was this afternoon in Volusia County, Florida. A woman in her 60s went outside to feed her animals when a tree fell on her and killed her, according to Volusia County Emergency Management.
The hurricane has already claimed hundreds of lives as it tore through Haiti and other Caribbean nations.
The National Hurricane Center downgraded the storm to a Category 3 hurricane with 120 mph winds at 2 a.m. ET today. The deadly storm could produce a potentially devastating storm surge of up to 10 feet over about 500 miles of coast that stretches from Florida, to Georgia and up into South Carolina.
As of 2 p.m. ET, Hurricane Matthew was 60 miles southeast of Jacksonville, Florida.
Severe flooding struck the beach in Jacksonville this afternoon, inundating the area with water and crushing dunes.
The storm is expected to move near or over the coast of northeast Florida and the coast of Georgia through tonight, then near or over the coast of South Carolina on Saturday. It could make landfall near Charleston as a Category 2 or 3 Saturday morning.
No other Atlantic storm on record has packed such powerful winds for such a prolonged period as Hurricane Matthew, ABC News meteorologists said.
The potential for a destructive storm surge, coupled with up to 15 inches of rain expected in isolated areas, has officials fearing catastrophic flooding.
Rick Knabb, director of the National Hurricane Center, told "Good Morning America" today, "This is a big major hurricane that is just offshore and it is fully capable of producing life-threatening storm surge."
"If you are in an area that emergency managers told you to evacuate and they’re telling you to go, you absolutely have to go now," Knabb said. "Your life could depend on it."
"We know from hurricane history that water takes nine out of ten lives in landfall," Knabb said. "Matthew is going to write some history. The key here is you don't want to be a part of it. I don't want to be writing up a report ... [on] fatalities and you're one of them."
About 3.1 million people were told to evacuate in Florida, Georgia and South Carolina. Officials in those states have urged coastal residents to head inland as the most powerful Atlantic storm in more than a decade continued on its path along the coast.
President Obama this morning urged residents to pay attention to their local officials. While the focus of the storm is on Florida right now, he warned Georgia residents to pay attention, as the storm will likely move north.
"We can always replace property," Obama said, "but we can't replace lives."
FEMA Administrator Craig Fugate told ABC News today, to residents in evacuation zones in Georgia and the Carolinas looking at initial reports and thinking, "'maybe it'll turn and it won't be so bad'--– you need to go now."
"Many of these areas have not had this level of flooding since, like, the late eighteen hundreds," he said. "We know some people don't evacuate."
"It is already too late for some people in Florida," he added. "Just stay where you're at, hold on, because it's just too dangerous to be outside."
More than 1 million customers were without power in Florida today as hurricane warnings cover hundreds of miles of Florida's east coast. A major hurricane has not struck Florida in over a decade.
A wind gust of up to 85 mph was reported today in St. Augustine, just south of Jacksonville.
A "hurricane warning" is in effect from Cocoa Beach, Florida, to Surf City, Florida, and a "hurricane watch" is in effect from north of Surf City to Cape Lookout, Florida.
More than 1.5 million Floridians were ordered to evacuate. Schools across most of the state were closed for the rest of the week as the governor deployed 3,500 National Guard troops to assist in storm preparations.
"I've never seen anything like this before. There were 22,000 people in our shelters," Gov. Rick Scott said on "GMA" today.
In Brevard County, Florida, the National Weather Service declared an extreme wind warning this morning as the western eye wall of the storm brushed by Cape Canaveral, home of the Kennedy Space Center, producing wind gusts in excess of 100 mph.
The National Weather Service in Jacksonville warned residents that "catastrophic damage" is anticipated for coastal areas and areas along the St. John's River. Forecasters in Jacksonville warned of a "worst-case storm surge scenario" and said "if a direct impact occurs, this will be unlike any hurricane in the modern era."
The governor said on "GMA," "We've been blessed that we haven't had a direct hit," however "with the hurricane force winds we're going to see a lot of storm surge."
Scott told reporters later this morning that he's particularly concerned about storm surge and there is a potential for significant flooding in Jacksonville. He said damage assessments are starting to come this morning from South Florida.
Scott told reporters later this morning so far there is "no reports of significant damage."
Scott said, even though the storm has passed half the state, "this is not over" and the storm "still has time to make a direct hit."
Scott had urged coastal residents to move to safe ground Thursday, warning, "This storm will kill you."
In Georgia, Gov. Nathan Deal has ordered mandatory evacuations east of I-95 along the entire Georgia coast, which is home to popular beach towns like Tybee Island.
Deal said this afternoon that crews are still extricating some people off of Tybee.
"There comes a point where we cannot jeopardize the lives of our first responders any further," Deal said.
The governor added that he knows people who evacuated are anxious to return home, but they should not put their lives in jeopardy by going back too soon.
Deal said on Thursday, "I don't intend to prosecute anyone for not leaving. ... I think Mother Nature will take care of them."
Deal said today that 9,000 people are in 30 shelters and 1,000 National Guardsmen have been deployed.
Deal told reporters Thursday night, "This is not Southern hospitality we are inviting to Matthew -- we hope he leaves as soon as possible."
In South Carolina, where the life-threatening storm is expected to make landfall around 8 a.m. Saturday, Gov. Nikki Haley is urging anyone who hasn't evacuated to leave today.
About 310,000 people have evacuated, Haley said this morning, adding that she asked everyone who hasn't left yet to evacuate, as the state prepares for major storm surges, winds, wet grounds, falling trees and power outages.
Speaking publicly for the last time before South Carolina went into storm mode, Haley said there is "nothing safe about what's getting ready to happen."
About 1.1 million people were ordered to move from coastal areas.
Most of the state's public schools and government officers are shuttered for the remainder of the week.
As North Carolina braces for intense winds and rains, Gov. Pat McCrory this afternoon called the storm potentially the worst flooding since Hurricane Floyd in 1999.
Coastal regions could see rainfall totals of 15 inches or more through tonight, Saturday and Sunday, McCrory said. Storm surge totals could reach 2 to 6 feet.
"What we feared is now happening in North Carolina," McCrory said.
He said the most immediate concern is life-threatening rain and water, adding that some rivers are already at high levels from past flooding.
Hurricane Matthew has caused major transportation disruptions for much of the U.S, with more than 4,200 flights cancelled between Wednesday and Saturday. The only airport that is currently closed is Savannah/Hilton Head International Airport; it is expected to reopen on Sunday at 8 a.m.
Amtrak suspended services in the southeast because of the severe weather.
More than 377,000 people were evacuated in Cuba as Hurricane Matthew approached the Caribbean island earlier this week, according to the United Nations. In Haiti, a local official told The Associated Press that 283 people had died, but other estimates report the figure to be much higher. Reuters reported that at least 478 individuals were killed as a result of Hurricane Matthew.