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Category 4 hurricane leaves a landscape of chaos

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Dozens killed across four states

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Florida and Georgia suffer power outages

(Adds latest death toll, details on dams in paragraphs 7, 11)

By Rich McKay, Joseph Ax and Andrew Hay

ATLANTA, Sept 27 (Reuters) - Tropical Depression Helene

brought life-threatening flooding on Friday to wide sections of

the U.S. Southeast, where at least 43 people have been killed by

a storm that swamped neighborhoods, triggered mudslides,

threatened dams and left more than 3.5 million homes and

businesses without power.

Before moving north through Georgia and into Tennessee and

the Carolinas, Helene hit Florida's Big Bend region as a

powerful Category 4 hurricane on Thursday night, packing 140 mph

(225 kph) winds. It left behind a chaotic landscape of

overturned boats in harbors, felled trees, submerged cars and

flooded streets.

By early Friday afternoon, the storm had been downgraded to

a tropical depression with maximum sustained winds of 35 mph (55

kph), the National Hurricane Center said.

But Helene's heavy rains were still producing catastrophic

flooding in many areas, with police and firefighters carrying

out thousands of water rescues throughout the affected states.

More than 50 people were rescued from the roof of a hospital

in Unicoi County, Tennessee, about 120 miles (200 km) northeast

of Knoxville, state officials said, after floodwaters swamped

the rural community.

Rising waters from the Nolichucky River were preventing

ambulances and emergency vehicles from evacuating patients and

others there, the Unicoi County Emergency Management Agency said

on social media. Emergency crews in boats and helicopters were

conducting rescues.

Elsewhere in Tennessee, Rob Mathis, the mayor of Cocke

County, ordered the evacuation of downtown Newport because of a

potential dam failure nearby. Mathis initially said the Walters

dam had suffered a "catastrophic failure" but later said the dam

"was breached" but there had been no major failure as yet.

The Tennessee Emergency Management Agency wrote on social

media that the Walters dam, which is located just across state

lines in North Carolina, had not failed. The agency said that

information came from Duke Energy ( DUK ), which operates the dam.

Madison McDonald, a Duke Energy ( DUK ) spokesperson, said, "we are

aware of the situation and we're sorting out the facts."

In western North Carolina, Rutherford County emergency

officials warned residents near the Lake Lure Dam to immediately

evacuate to higher ground, saying "Dam failure imminent."

But by 8 p.m. (0000 GMT), the county emergency officials

said that engineers had evaluated the dam "and determined it is

no longer at imminent risk of failure."

In nearby Buncombe County, landslides forced interstates 40

and 26 to close, the county said on X.

The extent of the damage in Florida began emerging after

daybreak on Friday.

In coastal Steinhatchee, Florida, a storm surge - the wall

of seawater pushed ashore by winds - of eight to 10 feet (2.4-3

meters) moved mobile homes, the National Weather Service said on

X. In Treasure Island, a barrier island community in Pinellas

County, boats were grounded in front yards.

The city of Tampa posted on X that emergency personnel had

completed 78 water rescues of residents and that many roads were

impassable because of flooding. The Pasco County sheriff's

office rescued more than 65 people overnight.

Officials had pleaded with residents in Helene's path to

heed evacuation orders, with National Hurricane Center Director

Michael Brennan describing the storm surge as "unsurvivable."

Some residents stayed put.

Ken Wood, 58, a state ferry boat operator in Pinellas

County, said he should have heeded evacuation orders rather than

riding out the storm at home with his 16-year-old cat, Andy.

"I'll never do that again, I swear," Wood said. "It was a

harrowing experience. It roared all night like a train. It was

unnerving. The house shook."

Down the hill from his house, the storm flooded some homes

with chest-deep salt water. One house caught fire and burned

down, shooting 30-foot flames in the stormy sky, he said.

"Old Andy seemed like he didn't care," Wood said. "He did

fine. But next time we leave."

Pinellas County Sheriff Bob Gualtieri said first responders

were unable to answer several emergency calls from residents

overnight due to the conditions. On Friday, county authorities

found at least five people dead.

Two others in Florida died, said Governor Ron DeSantis.

Georgia Governor Brian Kemp's office reported 15 storm-related

fatalities in that state, while North Carolina Governor Roy

Cooper said there had been two deaths there.

At least 19 people died during the storm across South

Carolina, the Charleston-based Post and Courier newspaper

reported, citing local officials.

Helene was unusually large for a Gulf hurricane, forecasters

said, though a storm's size is not the same as its strength,

which is based on maximum sustained wind speeds.

A few hours before landfall, Helene's tropical-storm winds

extended outward 310 miles (500 km), according to the National

Hurricane Center. By comparison, Idalia, a major hurricane that

struck Florida's Big Bend region last year, had tropical-storm

winds extending 160 miles (260 km) about eight hours before it

made landfall.