(This article, first posted at 11:15 p.m., was updated at 5:15 p.m. to reflect the latest National Hurricane Center advisory and current conditions in the Southeast)
Irma weakened to a tropical storm Monday morning and is expected to further weaken by Tuesday to a tropical depression. But this storm, while wounded, is still dangerous. Both storm surge and inland flooding, which cause the majority of deaths in tropical cyclones, remain a risk over the Southeast states.
— Jax Sheriff's Office (@JSOPIO) September 11, 2017
Charleston, S.C. was also under a flash flood emergency through 8:15 p.m.. “The combination of extremely high tides combined with heavy rain has resulted in widespread, dangerous flooding throughout Downtown Charleston,” the National Weather Service said.
Due to heavy rain and areas of flooding throughout South Carolina, the state’s emergency management division tweeted: “Dangerous conditions throughout much of South Carolina. Remain where you are if you’re safely able to do so.”
At 5 p.m., the storm center was plowing north-northwest through southern Georgia at 17 mph, about 150 miles south of Atlanta. Peak sustained winds had dropped to 50 mph, but higher gusts were reported.
Due to the storm’s enormous size, tropical-storm-force winds, capable of downing trees and causing outages, extended a lengthy 415 miles from the center. Atlanta’s Hartsfield-Jackson International Airport clocked a gust to 64 mph Monday afternoon.
In addition, tornadoes were possible from northeastern Georgia to southeastern South Carolina, where a tornado watch was in effect through 10 p.m.
Storm surge risk
Water levels will continue to be elevated above normally dry land along a section of Florida’s Gulf Coast and in coastal Georgia and southern South Carolina. A storm surge warning extended over these areas, and the National Hurricane Center warned Monday that “life-threatening” coastal inundation remained possible.
In areas where peak surge coincided with high tide, water levels were predicted to rise as much as 6 feet above normally dry land from the Georgia to central South Carolina coast on the storm’s Atlantic side, and from near Clearwater, Fla. to the state’s Big Bend area on the Gulf of Mexico side.
These are the hurricane center’s forecasts for the maximum water level at different locations if the surge peaks at high tide:
The National Weather Service reported that storm surge flooding in Jacksonville set a record Monday as water covered downtown streets.
— Kevin Rincon (@KevRincon) September 11, 2017
Surge flooding also occurred in Charleston, S.C., on Monday, reaching its worst around high tide midday Monday. “Avoid Downtown Charleston, roads already closing across the city,” the Weather Service tweeted.
This is White Point Garden is Downtown Charleston! Inundated with saltwater. pic.twitter.com/mloLiYzJy3
— Aaron Maybin (@Aaron_Maybin) September 11, 2017
The Weather Service said the water level in Charleston reached its third highest height on record.
Inland flood risk
Rain covered central and northern Georgia late Monday afternoon, as well as all of South Carolina, and almost all of Alabama. In many areas, the rain was falling heavily.
“Intense rainfall rates are leading to flash flooding and rapid rises on creeks, streams, and rivers,” the National Hurricane Center said.
The heaviest rainfall is expected to focus over northern Georgia, South Carolina and northern and eastern Alabama through Monday night.
“Significant river flooding will persist over the Florida peninsula in the wake of Irma and in Georgia, South Carolina and north-central Alabama, where additional heavy rains are expected,” the Hurricane Center said. “Portions of these states within the southern Appalachians will be especially vulnerable to flash flooding.”
Into Tuesday, the heaviest rain will spread north and west into the western Carolinas and Tennessee, and northern Mississippi. In these areas, the NWS predicted 2 to 4 inches of rain and locally higher amounts. The service also cautioned that local flooding could occur.
Through late Monday afternoon, widespread rainfall totals of 6 to 10 inches were reported over the Florida peninsula into southeast Georgia, with pockets of 10- to 15-inch totals.
Some of the 10-inch-plus totals fell over population centers such as Naples, Fort Myers, Melbourne and Fort Pierce:
In central Georgia into southern South Carolina, widespread amounts of 2 to 6 inches were reported.
Peak wind gusts from Irma
Irma made two landfalls Sunday: Over the Florida Keys and on Marco Island, Fla. Wind gusts to at least 90 mph were widespread over the peninsula, occurring far away from the storm’s center, due to its size.
Here are some of the peak wind gusts that have been logged by the National Weather Service: