The National Hurricane Center has said Irma is one of the most powerful Atlantic hurricanes recorded. The tropical storm is heading up the US through Georgia.
Hurricane Irma, one of the strongest Atlantic hurricanes ever recorded, started slamming the southeastern Caribbean islands early Wednesday as a Category 5 storm with devastating winds, heavy rains, and catastrophic storm surges.
As of 8 a.m. ET on Monday, the tropical storm was battering northern Florida with maximum sustained winds of 70 mph. The National Hurricane Center said the hurricane was cruising northwest toward Georgia at 18 mph.
The NHC reports that Irma made landfall at Cudjoe Key, one of the lower Florida Keys, at 9:10 a.m. on Sunday as a Category 4 storm, and made another landfall at Marco Island, on the west coast, at 3:35 p.m. on Sunday as a Category 3.
"There is the danger of life-threatening storm surge flooding along portions of the coasts of Florida, Georgia and South Carolina," the NHC wrote Monday morning. "Irma is a large hurricane, and hurricane-force wind
gusts and sustained tropical-storm force winds extend far from the center."
The National Weather Service's latest forecast still has many parts of Florida, as well as most of Georgia and South Carolina, in the storm's crosshairs.
The storm is expected to travel across Georgia on Monday, Alabama on Tuesday, and reach Tennessee as a tropical depression by early Wednesday morning.
Tropical storm warnings are in effect along the coasts of Florida, Georgia, and South Carolina, from Bonita Beach to the Okaloosa/Walton County Line, from Jupiter Inlet to the South Santee River, and in Lake Okeechobee.
Storm-surge warnings are in effect from South Santee River south to the Flagler/Volusia County line, from Cape Sable northward to the Ochlockonee River, and in Tampa Bay. Those areas could face "life-threatening inundation" from the quick rise in water caused by a hurricane's strong winds.
Irma is now a tropical storm on the Saffir-Simpson scale, which measures a hurricane's strength based on its wind speeds. The scale goes up to 5, but if it had been extended to classify Irma's highest sustained wind speeds of 185 mph, the storm could have been considered Category 6 at one point. That's not an official designation, though.
Some hurricane-force gusts above 75 mph are still being reported in northern Florida. The winds have also been churning up tornadoes, and some counties in northeast Florida and southeast Georgia and South Carolina could face tornadoes.
Part of what makes this storm so dangerous is its sheer size — hurricane-force winds still extend up to 60 miles from Irma's center, and tropical-storm-force winds extend up to 415 miles, according to the NHC.
Florida's peninsula is only about 140 miles across at its widest, so Irma engulfed the entire state.
Many areas, including Miami and the southwest coast where the hurricane made landfall on Sunday, saw storm surges many feet high, which flooded roads and beached boats.
The National Hurricane Center suggests that if the storm surge hits at high tide, water levels could rise 2-4 feet above ground from Cape Sable to Captiva and in and around Tampa Bay, 3-5 feet from Captiva to Ana Maria Island, 1-2 feet from North Miami Beach to Cape Sable including the Florida Keys, 4-6 feet on the east coast of Florida from South Santee River to Fernandina Beach, 4-feet on the west coast of the state from Clearwater Beach to Ochlockonee River, and 3-5 feet from Fernandina Beach to Jupiter Inlet.
The NHC expects an additional inch of rain in the Florida Keys, and another 1 to 3 inches in central Florida.
Northern Florida into southern Georgia can expect another 3 to 6 inches, bringing the storm totals to 8 to 15 inches.
Central Georgia, eastern Alabama, and southern South Carolina could get 3 to inches of rain, with some areas seeing up to 10 inches.
The Florida Panhandle, western Alabama, northern Mississippi, southern Tennessee, northern Georgia, northern South Carolina and western North Carolina could also get 2 to 4 inches.
Though Irma's catastrophic hurricane status was reclassified to a tropical storm by Monday, forecasters advise residents to heed the advice of local officials and get ready if they are in the projected path of the storm.
An estimated 7 million people were ordered to evacuate in Florida. The Florida Keys and the southern tip of the state have most likely seen the worst effects of the storm as Irma continues to weaken over land.
Forecasters are predicting the storm will travel over Georgia, Alabama, Tennessee, and parts of Missouri and Arkansas. But Irma is so big that the Carolinas are projected to see heavy rainfall and even storm surge on the coasts.
"Since Irma is a large hurricane, [forecast] users are reminded to not focus on the exact forecast track since tropical-storm and hurricane-force winds and life-threatening storm surge extend far from the center," Daniel Brown, a senior hurricane specialist at the NHC, wrote on Tuesday.
"Everyone in hurricane-prone areas should ensure that they have their hurricane plan in place."