Helene strengthened into a Category 4 hurricane hours ahead of its expected landfall on Florida’s northwest coast Thursday night, and forecasters warned that the enormous storm could create a “nightmare” surge in coastal areas and bring dangerous winds and rain across much of the southeastern U.

Hurricane Helene made landfall in Florida’s Big Bend as a Category 4 storm late Thursday, knocking out power in over a million homes and businesses and causing at least one death in the state as the National Hurricane Center warned of life threatening winds and catastrophic storm surges.

Hurricane warnings and flash flood warnings extend far beyond the coast up into northern Georgia and western North Carolina.