Rescuers were on Friday surveying the damage after the most powerful storm to hit the Florida Panhandle in recorded history killed at least seven people. Michael flattened homes, plunged communities into darkness and ravaged whole neighborhoods.

"This hurricane was an absolute monster," Florida Gov. Rick Scott said Thursday. "And the damage left in its wake is still yet to be fully understood." 

Officials warned that the number of dead was likely to rise as search crews struggled to gain access to ravaged areas and sift through the piles of debris.

Michael is not a spent force. The National Hurricane Center on Friday warned the storm was gaining strength with maximum increasing to 65 mph and would remain dangerous as it moves off toward the Atlantic Ocean through the weekend.

Tropical storm-force winds extended as far as 275 miles from the center and flash flooding is still a risk for parts of the Carolinas and the southern mid-Atlantic.

Mike McAuliffe, 30, stayed in Panama City Beach with his wife, Rebecca, 33, during the storm.  

"It's easily the scariest thing I've ever lived through," McAuliffe said in an interview. The couple were assessing damage and trying to help neighbors on Thursday.

Rebecca McAuliffe said: "You can't even recognize some of the areas in town."

Michael made landfall in Mexico Beach, Florida, on Wednesday just shy of Category 5 hurricane strength, with winds gusting at 155 mph. While the storm weakened through the night as it passed over Georgia, it still proved deadly.

Almost one-and-a-half million customers were without power from Florida to Virginia on Thursday night.  

The damage could be particularly severe for the Carolinas, which are still cleaning up from Hurricane Florence.

"We need people in South Carolina and North Carolina to remain vigilant and be careful. This is a strong tropical storm pushing through," Brock Long, administrator of the Federal Emergency Management Agency, said on "Today."

Sharon Black, who lives in Wilmington, North Carolina, worried that Michael's winds would blow away debris still piled up on front lawns from Florence.

"I spent three or four weeks trying to take care of things" after Florence, Black said, adding that she hoped this storm would take it easy on the Carolinas.  

North Carolina Gov. Roy Cooper said 6 inches of rain had fallen in parts of the state, triggering a mudslide in McDowell County, 100 miles west of Charlotte.