Rescue operations sought to find survivors and deliver supplies across Florida, Georgia, North Carolina, South Carolina and Tennessee in areas where torrential rains brought by Hurricane Helene caused havoc.

Residents face power cuts, supply shortages, blocked roads and broken communication lines in often mountainous terrain.

Republican candidate Donald Trump will on Monday visit Valdosta in Georgia -- an epicenter of the flooding destruction, and also a key state in the tight election being held in just five weeks' time.

Trump's Democrat opponent Vice President Kamala Harris canceled campaign events to return to Washington for a briefing on the federal response, while President Joe Biden was due to speak on Monday morning from the White House.

Biden, who has approved federal aid for several states in the wake of the disaster, plans to travel to hard-hit areas this week, "as soon as it will not disrupt emergency response operations," the White House said Sunday, adding that Harris would do the same.

North Carolina Governor Roy Cooper said Monday that hundreds of roads had been destroyed and many communities "wiped off the map."

"This is an unprecedented storm," he told reporters. "We're working to surge supplies in. The emotional and physical toll here is indescribable.

"Rivers are still rising, so the danger is not over."

He said the long-term rebuilding plan would need to confront a reality of more extreme weather, "but right now, we're concentrating on saving lives and getting supplies to people who desperately need them."

Scientists say climate change likely plays a role in the rapid intensification of hurricanes, because there is more energy in warmer oceans for them to feed on.

At least 100 people were killed -- 39 in North Carolina, 25 in South Carolina, 17 in Georgia, 14 in Florida, four in Tennessee and one in Virginia, according to tallies from local authorities compiled by AFP. That total was expected to rise.

Nearly two million households and businesses remained without power on Monday, according to tracker poweroutage.us.

Helene slammed into Florida's northern Gulf shore as a huge Category Four hurricane late on Thursday night with winds of 140 miles (225 kilometers) per hour.

Even as it weakened, it tore a path of destruction stretching inland more than 500 miles.