Flash flood emergencies are in effect in Georgia and the Carolinas.
Helene made landfall in Florida's Big Bend region Thursday night as a massive Category 4 hurricane -- the strongest hurricane to make landfall in the Big Bend on record.
Helene has since weakened to a tropical storm and is now pushing through Georgia and the Carolinas, bringing catastrophic rainfall and life-threatening flash flooding as the storm moves toward Tennessee.
Helene, currently a Category 1 hurricane, is forecast to make landfall as a major Category 4 hurricane with winds up to 130 mph.
Landfall is forecast between 8 p.m. and 11 p.m. Thursday in Florida's Big Bend region.
Mandatory evacuations are in effect in parts of at least 20 Florida counties, including Taylor, Sarasota, Gulf and Hillsborough.
North Carolina and Georgia have declared states of emergency ahead of Hurricane Helene, their governors announced on Wednesday.
"The current forecast for Hurricane Helene suggests this storm will impact every part of our state," Georgia Gov. Brian Kemp warned in a statement. "We are not taking anything for granted, which is why I have directed appropriate state agencies to work around the clock to ensure we're prepared for whatever is heading our way."
The heavy rain, flash flooding and winds are also threatening the mountains and Piedmont areas of North Carolina, North Carolina Gov. Roy Cooper said. The state is preparing water rescue teams and urban search and rescue teams to help respond to the storm, he said.
Florida A&M University, the University of Tampa, the University of Florida and Florida State University’s Tallahassee campus have all announced closures ahead of Hurricane Helene’s landfall. The University of Tampa is under a mandatory evacuation order.
Younger students will also be out of school. Only six out of Florida's 67 counties have public school districts that will remain open on Thursday. Public schools are also closed in Atlanta on Thursday and Friday.
-ABC News’ Alex Faul
