(Image source from: Al Jazeera)

Rescue and search efforts began in the Florida Panhandle as the United States army, state authorities and volunteers dealt with Hurricane Michael's wake on Friday.

A Category 4 storm, Michael, smashed into Florida's northwest coast near the small town of Mexico Beach on Wednesday with 250 kilometers per hour winds.

Michael has killed at least seven and was downgraded to a tropical storm overnight Thursday.

The U.S. Army personnel used heavy apparatus to push a path through debris in Mexico Beach to let rescuers look for trapped residents, casualties or survivors, as Blackhawk helicopters circled overhead.

Rescuers from the Federal Emergency Management Agency used dogs, drones, and GPS (Global Positioning System) in the search.

Michael, the third-most powerful hurricane ever to hit the U.S. mainland, continued its path northeast to with 80km/h winds, bringing "life-threatening" flash flooding to Georgia and Virginia, the National Hurricane Center (NHC) reported.

Florida Governor Rick Scott told the Weather Channel the damage from Panama City down to Mexico Beach was "way worse than anybody ever anticipated."

Approximately 950,000 homes and businesses were without power in Florida, Alabama, the Carolinas, and Georgia on Thursday.

The number of people in emergency shelters was expected to swell to 20,000 across five states by Friday, said Brad Kieserman of the American Red Cross.

Michael pummeled communities across the Panhandle and turned streets into roof-high waterways.

Around 32km south of Mexico Beach, floodwaters were over 2.1 meters profound near Apalachicola, a town of more or less 2,300 residents, hurricane center chief Ken Graham said. Wind damage was as well apparent.

"Our biggest thing is the downed lines and the downed trees," said Apalachicola Mayor Van Johnson.

Brad Rippey, a meteorologist for the U.S. Agriculture Department, said Michael severely damaged cotton, timber, pecans, and peanuts, causing estimated liabilities as high as $1.9bn and affecting up to 1.5 million hectares.

Michael as well disrupted energy operations in the U.S. Gulf of Mexico as it approached land, cutting crude oil production by over 40 percent and natural gas output by about one-third as offshore platforms were evacuated.

-Sowmya Sangam