The U.S. National Hurricane Center (NHC) in Miami said as of midday Tuesday, Hurricane Sally is a Category 1 storm, packing maximum sustained winds of 80 mph, and is located about 115 miles south of Mobile, Ala., "inching" northwest at 2 mph.
Sally should reach land near the Alabama-Mississippi state line by late Tuesday or early Wednesday, bringing the threat of a storm surge of up to 7 feet along Alabama's coast, including Mobile Bay.
“A saying the National Weather Service has is 'hide from the wind, run from the water,'” National Weather Service Meteorologist John De Block said Tuesday during a news conference. “Now is the time to run from the water.”
The governors of Louisiana, Mississippi and Alabama have all declared states of emergency, and President Trump issued emergency declarations for parts of those states in advance of the storm. Mandatory evacuations have been ordered in some areas.
“This is not worth risking your life,” Alabama Gov. Kay Ivey said during a news conference Tuesday while urging residents near Mobile Bay and low-lying areas to leave.
Florida Gov. Ron DeSantis has declared a state of emergency for the Panhandle counties of Santa Rosa and Escambia as the storm's track shifted east.
But hours before the worst of Sally is set to arrive, coastal areas are also dealing with floodwaters.
Officials closed the causeway to Dauphin Island in Alabama after many residents and visitors evacuated on Monday.
“I’m not gonna hang around if it’s coming right to us,” Sharon Dixon told FOX10.
The Alabama Department of Transportation closed the Bankhead Tunnel in Mobile in anticipation of the storm's arrival.
Sandbags were also placed in front of the doors to keep the tunnel from being inundated with storm surge.
Officials said the tunnel will be reopened after the storm surge recedes and conditions are safe.
Mobile was under a "Level 3 Alert" in advance of the storm, with many residents filling grocery stores and gas stations on Monday. By Tuesday morning, downtown Mobile was nearly deserted, with businesses boarded up and protected by sandbags.
Many who were stocked up for Hurricane Marco said they were still returning to get more.
"We were already prepared – so we decided to get more this time to be prepared because the rain is going to stay for about three or four days and we are not going to get out," one woman told FOX10.
Two unoccupied riverboat casinos broke loose and ran into docks on Tuesday morning as the outer edges of the storm began impacting the area.
In Gulfport, Miss., white plastic bags hung over some gas station pumps, showing they were out of gas, according to the Associated Press.
The Pascagoula Police Department in Mississippi tweeted that multiple roads were blocked due to "standing water" as storm surge impacted the area.
"The roads are barricaded for your safety. Please do not remove or go around barricades," police tweeted. "Stay safe Pascagoula!"
Flooding and road closures were also reported in Florida, including in the Pensacola area.
Officials said a three-mile bridge that connects Pensacola to Gulf Breeze was shut down due to a barge that broke loose and ended up wedged under the bridge.
By late morning Tuesday, hurricane warnings stretched from east of Bay St. Louis, Miss., to Navarre, Fla.
The Okaloosa County Sheriff's Office also shared a video of the storm surge in Destin.
Some additional strengthening is possible, but forecasters have said it doesn’t matter what category Sally is because the slow movement of this storm will be the biggest danger with a prolonged water event.
A life-threatening storm surge of 7-9 feet just east of the center of the storm can be expected as well as inland flooding, and hurricane-force winds for many hours will be a major danger in the next 24-36 hours for this area.
Severe flash flooding can also be expected, with a widespread area of 10-20 inches of rain from the Central Gulf Coast to the Florida Panhandle.
Some isolated spots could even receive upwards of 30 inches of rain.
Fox News' Janice Dean and the Associated Press contributed to this report.