Six people have been killed as a result of Hurricane Michael, which hit the Florida Panhandle as a Category 4 storm Wednesday and has continued wreaking havoc on its trek through Georgia and the Carolinas weakening to a tropical storm Thursday.

Four people in Florida, one in Georgia, and one in North Carolina were identified by federal officials Thursday as casualties in the storm, but the Federal Emergency Management Agency chief said that number is expected to grow over the next few days.

"Unfortunately in these types of things as we go through and sift through damage, ultimately those who didn't heed warnings, particularly around the Mexico Beach area — we typically see deaths climb, unfortunately," Brock Long, FEMA administrator, told CBS Thursday.

Meteorologists documented sustained winds of 155 miles per hour when Michael made landfall in Mexico Beach, Fla., Wednesday afternoon. It's now the most powerful storm to ever hit the northern, Gulf Coast side of Florida.

[Read: Hurricane Michael leaves 1.2 million in the dark from Florida to Virginia]

The storm spared capital city Tallahassee its worst but shredded smaller towns closer to the coast, including Callaway, Panama City, Greensboro, Mexico Beach, and Saint George Island. Homes in the area were ripped from their foundations, large trees were uprooted, and power lines were sprawled across streets and fields.

Seminole County's emergency management agency director, Travis Brooks, told ABC News there was "complete and total devastation" in the area.

In nearby Leon and Franklin counties, 98 to 100 percent of electric customers are without power. A total of 400,000 households were without power Thursday night, according to the Tallahassee Democrat.

"So many lives have been changed forever," Florida Gov. Rick Scott, a Republican, said during a press conference Thursday. "So many families have lost everything."

By Thursday morning, the storm had dropped from a Category 4 down to a Category 1 then to a tropical storm. Even with winds of 50 miles per hour, the National Hurricane Center warned that people as far as 230 miles from its center could see serious wind damage.

"Life-threatening flash flooding and damaging winds are ongoing across portions of North Carolina and Virginia," the center said Thursday evening.

Duke Energy estimated up to 500,000 power outages in North Carolina and South Carolina.