At least four people were reported dead on Saturday amid Isaias after it made landfall late on Friday on Florida’s panhandle as a category 2 hurricane, according to authorities.

The storm also took down trees, knocked out electricity for hundreds of thousands and flooded highways – but as Saturday evening approached, the region was reopening.

Despite warnings of storm surges ahead of the storm, several major routes along the coast were open by daybreak on Saturday and free of downed trees and power lines typically seen after major hurricanes.

Two of the deaths reported during Isaias occurred in Escambia county, Florida, and two others were reported in Alabama, as the storm moved inland, local officials said. Of those deaths, one each occurred in Escambia and Birmingham, Alabama, when trees fell on homes.

Another person whose death was linked to Isaias was found in a closed garage with a running generator in Escambia county. Four members of that person’s family have been transported to the hospital with carbon monoxide poisoning, the Escambia sheriff’s office said.

“Don’t run any generators inside your home, it can be very, very hazardous,” Florida governor Ron DeSantis said in a press conference.

People retrieve belongings from a collapsed boat house in the aftermath of Hurricane Isaias in Destin, Florida, on Saturday. Photograph: Gerald Herbert/AP

In Alabama, governor Kay Ivey said Isaias – predicted to dissipate on Sunday – “cannot clear fast enough”.

Meanwhile, though it had weakened on Saturday to a post-tropical cyclone as it passed through central Alabama, Isaias still posed flooding and tornado threats as it moved inland, forecasters and officials warned.

Hurricane-force winds in the Florida panhandle blew the roof off a Pensacola hotel, and the city’s mayor said the airport “took some damage”. The storm flattened a boathouse in Destin and ripped away part of the facade of a high-rise in Panama City Beach.

A worker in a condominium parking lot swept piles of the building’s insulation while others put back beach chairs that had been tossed about.

Lee Glessner begins to remove tree limbs from a fallen tree block a road after the landfall of Hurricane Isaias in Milton, Florida, on 10 October. Photograph: Dan Anderson/EPA

“Remember, there can still be flooding from rising rivers,” Jared W Perdue, the secretary of Florida’s state transportation department, said at a news conference. “I’m just going to remind all of you – please, if there’s standing water or flowing water on top of a road, please do not drive through it.

“It does not have to be that deep, and it can wash away your car, it can wash away a human, it can become very dangerous very quickly.”

Nearly 550,000 customers were still without power across Florida, Alabama and Georgia on Saturday afternoon as those in the path of the storm began the cleanup process, according to PowerOutage.us. Though still high, the number of outages was down from more than 900,000 earlier on Saturday.

Dark clouds loom over a historic Catholic church on Friday in Mobile, Alabama. Photograph: Octavio Jones/AP

Storm surge and tropical storm warnings associated with Isaias by then had been discontinued, the National Hurricane Center (NHC) warned there would still likely be “considerable impacts” associated with Isaias across much of southern Alabama, Florida’s panhandle and south-western Georgia.

“Flash, urban and river flooding is possible across the region,” the NHC said in a Saturday-morning advisory, adding that there was a considerable potential for flash flooding and landslides across the southern Appalachians. “A risk for tornadoes will persist … through [Saturday] afternoon across parts of the eastern Florida panhandle, Georgia and the Carolinas.”

Isaias through Sunday is expected to produce rainfall amounts of 4-8in across southern Alabama, Florida’s panhandle and Big Bend regions, and south-west Georgia. Localized totals up to 15in are possible, particularly within rain bands across the Florida panhandle and Big Bend.

In an aerial view, an apartment complex is seen after the roof was blown off when Hurricane Isaias passed through the area on Saturday in Milton, Florida. Photograph: Joe Raedle/Getty Images

Across much of the remainder of the south-east US, rainfall amounts of 2-5in are expected, and localized higher amounts up to 10in are possible, especially across the southern Appalachians and coastal Carolinas.

The hurricane’s maximum sustained winds were 105mph (169km/h). That was intense enough to sound like “a train whistle”, Tim Mowry told the Associated Press after enduring the storm as his home in Pensacola, Florida.

Mowry described losing power on Friday afternoon but said could rely on a generator. He said his son tried to drive to his home after his place about 15 minutes away lost power but had to turn around because downed trees and power lines blocked the road.

All things considered, Mowry said he was “really fortunate” with respect to how he fared during Isaias.

Along Alabama’s Gulf coast, authorities in Mobile reported numerous downed trees and power lines.

Maranie Adams, who rode out the storm with her family and their chickens in Gulf Shores, Alabama, said the winds rocked their home, but it was nothing like Hurricane Sally, which left water under their elevated house.

“I feel very much more relieved today,” she said.

Donald Trump has allowed the Federal Emergency Management Agency (Fema) to provide resources to Georgia to help grapple with the ongoing storm, including possible tornadoes, the agency said on Saturday.

Several roads have already been blocked by fallen trees around Atlanta, local outlets have reported.

People line up for gas at one of the few open stations after the landfall of Isaias in Milton, Florida, on Saturday. Photograph: Dan Anderson/EPA

Trump previously approved emergency declarations for Florida and Alabama ahead of the landfall of Hurricane Isaias.

While the stronger El Niño seemed to limit the number of hurricanes in the Atlantic for the year so far, Isaias forming in October with maximum sustained winds of 105mph marked a stark contrast from historical trends.

The National Oceanic and Atmospheric Administration (Noaa) predicted a quiet year in terms of hurricanes at the beginning of a season that officially begins annually on 1 June. Noaa anticipated between three and six hurricanes, well below the average of seven. An August forecast from Noaa cut the expected number to between two and six.

Isais is one of the two latest-forming Atlantic hurricanes on record, tying a record set on 8 October 1905. Otherwise, the second-latest date for the first Atlantic hurricane was 11 September – in 2002 and 2013.

None of the eight previous named storms of the 2026 Atlantic season intensified above tropical storm status.

The Associated Press contributed reporting