The third-most powerful storm ever to strike the US mainland headed northeast to soak Georgia and the Carolinas on Thursday, leaving the Florida Panhandle to assess the devastation left by Hurricane Michael. 

The hurricane claiming at least two lives in Florida, both from falling debris.

The Category 4 storm was the fiercest to hit the Florida Panhandle and the third-most powerful storm ever to strike the US mainland.

Michael's strength has waned as it churns through Georgia - downgraded to a tropical storm, with top sustained winds of 60 miles per hour.

More than 700,000 homes and businesses were without power in Florida, Alabama and Georgia.

The rapid intensification of the storm caught many by surprise, making landfall midday Wednesday near Mexico Beach, Florida, where homes were submerged in floodwaters and top sustained winds reached 155 miles per hour. 

The governors of North and South Carolina urged residents, many of whom are still recovering from Hurricane Florence less than a month ago, to brace for heavy rain, storm-force winds and more flooding.