Florida residents are preparing for a heavy blow from Hurricane Helene as it moves toward Tallahassee, where it’s expected to make landfall Thursday night with winds reaching 140 mph and life-threatening storm surges.

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.

Storm surge is a bigger killer than wind when a major hurricane hits shore. The areas in the path of Hurricane Helene are more susceptible to surge than other parts of Florida's coast.