GEOFF BENNETT: Welcome to the "News Hour."

The devastating impact of Hurricane Helene is being felt far and wide across the South tonight.

At least 40 people are dead in four states.

Millions are without power.

And there have been harrowing air rescues from Florida to Tennessee.

And although the Category 4 hurricane is now a tropical depression, the threat is not over yet.

Christopher Booker has the latest.

CHRISTOPHER BOOKER: Helene's fury unleashed on the Florida Gulf Coast.

Coming ashore last night just east of Tallahassee as a Category 4 hurricane, the storm brought sheets of blinding rain and whipping winds of 140 miles an hour.

Storm surge threatened to wash cars off roads.

Ocean swells grew so high that it carried these boats from the water and smashed them into homes.

MAN: Oh, my goodness.

Oh, my goodness.

CHRISTOPHER BOOKER: Flooded streets resemble rivers.

Entire neighborhoods look more like lakes.

This man in Cedar Key tried to check on family.

MAN: I was trying to make it to my mama's house, but it's neck deep here.

I'm not able to get any further.

Oh, man.

CHRISTOPHER BOOKER: It prompted thousands of high-water rescues from Florida up through the Carolinas, first responders out in boats to rescue people trapped in their homes.

In South Pasadena, Florida, firefighters literally battled fires and floods.

And in one daring rescue, the Coast Guard airlifted a man and his dog from their stranded sailboat off the coast of Florida's Sanibel Island, with the storm bearing down.

Still, Helene claimed lives in multiple states from fallen trees, debris, and possible tornadoes, many of them in Georgia, where Governor Brian Kemp said the threat was still very real.

GOV.

BRIAN KEMP (R-GA): It is still very dangerous out there.

Even though the winds are starting to die down, there's still trees literally falling.

CHRISTOPHER BOOKER: In the mountains of Asheville, North Carolina, up to 10 inches of rain sent floodwaters roaring past the Biltmore.

And in Tennessee, dozens of people had to be airlifted from a hospital engulfed by the rising river.

For more than four million people across the South tonight, they're left in the dark.

And returning power to some customers, officials say, could take days.

Helene has now weakened to a tropical depression, but it still threatens millions further inland, hovering over the Tennessee Valley through the weekend.

Its sheer size can only fully be comprehended from space, spanning from Missouri to Virginia down to Georgia, where streets and neighborhoods were submerged today, catching many off guard.

ALESE MCGHEE, Peachtree Park Resident: I just didn't expect this to happen.

Like, living over here, it wasn't something that came, like, across my mind.

This is so crazy.

CHRISTOPHER BOOKER: Back in Florida's Big Bend, it's been a devastating trifecta of hurricanes.

Helene made landfall mere miles from where Idalia struck just last year.

And many of the same communities are still reeling from Hurricane Debby just one month ago.

Governor Ron DeSantis today: GOV.

RON DESANTIS (R-FL): And the early reports we have received is that the damage in those counties that were really in the eye of the storm has exceeded the damage of Idalia and Debby combined.

In Riverview, just outside of Tampa, Randy and Bonnie Hann's home was inundated with water from the nearby Alafia River.

They stayed with family last night, but came back early this morning.

RANDY HANN, Hillsborough County Resident: We came back and we were able to get down the street.

And we had all the doors taped and sandbagged, but that water finds a way of getting in.

CHRISTOPHER BOOKER: They have been in their home since 1975.

And although it has flooded before, they say it's never been this bad.

But despite the damage, they have pledged to rebuild no matter how long it takes -- Geoff.

GEOFF BENNETT: And, Christopher, you're there in the Tampa area.

Tell us more about what you're seeing.

CHRISTOPHER BOOKER: You know, as we drove in from the east toward Tampa, we didn't see a lot of downed trees or that much water.

But as we learned through the day, Tampa and nearby Tallahassee were actually spared the brunt of the storm.

But here on this street, which is right next to the Alafia River, nearly every single home was flooded.

As you can see behind me, people have been bringing out their damaged furniture, spending the day assessing the damage and trying to figure out what it's going to take to get their homes back to normal.

GEOFF BENNETT: What else have you heard from officials there about what the last 24 hours have been like for folks?

CHRISTOPHER BOOKER: I had a conversation earlier today with a spokesperson from the Hillsborough County Fire Rescue who said that between 11:00 p.m. and 6:45, they rescued 500 people.

He also said the sheriff department rescued 400 people.

So in just under eight hours, they rescued nearly 1,000 people.

For comparison's sake, two months ago, there was a tropical storm.

They rescued 11 people.

He said that the storm surge actually exceeded what they were expecting and it landed somewhere between four - - it rose between four and seven feet.

And they received nearly 1,200 calls during that nearly eight-hour period.

On a normal night, they might get two calls for fires.

Last night, they had 47.

He also said that this storm was an eye-opening event for Hillsborough,that this is an area that's used to storms, but last night was different.

GEOFF BENNETT: That is Christopher Booker in Riverview, Florida, for us tonight.

Thanks so much for being with us.

CHRISTOPHER BOOKER: Thank you.