Rivers swollen by Hurricane Sally's rains threaten more misery for some residents of the Florida Panhandle and south Alabama on Thursday.

It comes as the storm's remnants are forecast to dump as much as a 1ft of rain and spread the threat of flooding to Georgia and the Carolinas.

Coastal residents, meanwhile, looked to begin the recovery from a storm that turned streets into rivers, ripped roofs off buildings, knocked out power to hundreds of thousands and killed at least one person.

Florida Governor Ron DeSantis warned residents and visitors in flooded areas they will need to remain vigilant as water from the hurricane subsides because heavy rains to the north are expected to cause flooding in Panhandle rivers in the coming days.

"So this is kind of the initial salvo but there is going to be more that you're going to have to contend with," Mr DeSantis said at a news conference in Tallahassee.

At least one death was blamed on the hurricane.

Tony Kennon, mayor of Orange Beach, Alabama, said one person in the popular holiday destination died and another is missing as a result of the storm.

He said he could not immediately release details.

Mr Kennon added the damage in Orange Beach is worse than that from Hurricane Ivan, which hit 16 years to the day earlier.

In a Facebook briefing for city residents, he said: "It was an unbelievably freaky right turn of a storm that none of us ever expected."

Sally blew ashore near Gulf Shores, Alabama, on Wednesday morning as a major hurricane with 105mph winds.

It moved slowly, exacerbating the effect of heavy rains.

More than 2ft fell near Naval Air Station Pensacola, and nearly 3ft of water covered streets in the centre of Pensacola, the National Weather Service reported.

Floodwater swamped parked cars in the city before receding.

Sally weakened to a tropical depression late on Wednesday and picked up speed.

By early Thursday morning, it was producing torrential rains over eastern Alabama and western and central Georgia.

Forecasters said there is a threat of tornadoes on Thursday across southern Georgia and northern Florida.

More than 22,000 homes and businesses in Georgia were without power by early Thursday morning, according to the poweroutages.us website.

News outlets reported some trees were toppled in Georgia as remnants from the storm moved into the region.

Well over a half million homes and businesses were without electricity in Alabama and Florida, according to the power outages website.

Many faced extended time without power.

At least eight waterways in south Alabama and the Florida Panhandle are expected to hit major flood stage by Thursday.

Some of the crests could break records, submerge bridges and flood some homes, the National Weather Service warned.

The National Hurricane Centre said the system is now moving through south-east Alabama, will cross over central Georgia on Thursday and reach South Carolina on Thursday night.

Flash flooding and some river flooding is possible in each state.

Up to 1ft of rainfall is forecast in some parts of south-east Alabama and central Georgia by Thursday night, posing a threat of significant flash flooding and "minor to moderate" river floods.

In South Carolina, as much as 10 inches of rain is possible and up to eight inches in North Carolina.

The hurricane centre is tracking two other Atlantic storms.

Hurricane Teddy was strengthened to a Category 2 hurricane early on Thursday with maximum sustained winds of 105mph, it said.

The storm is currently located about 625 miles east-northeast of The Lesser Antilles.

Teddy is moving towards the north-west at about 12mph, the general motion it is expected to continue through the weekend.

Additional strengthening is forecast to happen during the next couple of days and Teddy could become a major hurricane on Thursday night or Friday, the centre said.

Tropical Storm Vicky is expected to dissipate in the Atlantic in the coming days.