Helene has left the bridge network across the Nolichucky River in Greene County, Tennessee -- along the Tennessee-North Carolina border -- severely compromised.

While the bridge on Asheville Highway remains standing, it faces significant damage. Residents south of the river, especially in the vicinity of Highway 107, are facing critical challenges, with many of them isolated cut off from basic services like food, water and medical care, officials said. Efforts are underway to bring aid to isolated areas, officials said.

Greene County is also facing a looming water crisis after the water intake at the Nolichucky River was destroyed by debris. The Tennessee Valley Authority assessed the condition of the nearby dam and declared it under "Condition Red.”

The county’s water supply is in critical condition, with only 36 to 48 hours of reserves left. The local water commission has urged residents to conserve water.

-ABC News’ Jason Volack

Helene’s "fierce" and "unstoppable" storm surge has left some homes in Florida completely obliterated and "just rubble," Florida Gov. Ron DeSantis said at a news conference Saturday.

The storm surge was more than 15 feet in some spots -- much more significant than from other recent storms, he said.

Eleven people in Florida were killed from the storm, but none of the fatalities were in Taylor County, where Helene made landfall, the governor said.

He credited local officials and residents for heeding evacuation orders.

"If you had told me there was going to be 15 to 18 feet of storm surge, I would have expected multiple fatalities. The fact that there weren’t any here is a testament to the preparedness of the community," he said.

Residents of Pasco County, Florida, just north of Tampa, are facing "a level of devastation in our county that, quite honestly, I haven't seen in the 20-plus years that I've lived here," county administrator Mike Carballa said.

Pasco County’s emergency center received about 400 to 500 calls for service early Friday morning after landfall, Carballa said. Of those calls, crews were only able to answer about 20%, he said.

There were fires that first responders saw but could not initially reach, which Carballa called "heart wrenching."

"We felt very, very helpless," he said.

Despite Helene's devastation, officials said they saw residents helping their neighbors, like by taking them to safety in boats.

The initial response phase has ended and officials are now moving into damage assessment, Carballa said.

-ABC News’ Victoria Arancio

The storm surge, wind damage and inland flooding from Hurricane Helene was catastrophic.

Friday’s flooding in western North Carolina surpassed records that stood for more than a century. The French Broad River in Asheville, North Carolina, peaked at 24.67 feet, breaking the previous record of 23.1 feet from 1916.

More than 2 dozen river gauges are in major flood stage due to this historic rainfall. Many of these rivers will take several days to return to normal after reaching record-high levels on Friday.

On Saturday, parts of North Carolina, Tennessee and Virginia remain under flash flood emergencies.

Helene, now a post-tropical cyclone, is stalling over the Tennessee Valley, bringing more rain and scattered gusty winds through the weekend.

-ABC News’ Daniel Amarante