Isaias struck Florida as a Category 2 hurricane on Friday before weakening and bringing tropical-force winds to Alabama. Two storm-related deaths were reported in each state.
The storm damaged homes, trees, and other structures.
In Pensacola, Destin, and Panama City Beach, strong winds tore roofs and facades off hotels and condominiums.
Nearly 900,000 customers across Florida and Alabama lost power shortly after landfall.
Meanwhile, flash flood warnings were issued across Georgia, the Carolinas, the Appalachian region, the Tennessee Valley, and the mid-Atlantic as heavy rainfall threatened more areas.
At the same time, in the Pacific, Hurricane Simon strengthened into a Category 4 storm approaching Mexico, alongside Tropical Storm Rachel threatening northern Mexico and Southern California.