At least 24 people died in South Carolina, 17 in Georgia, 11 in Florida, 10 in North Carolina and one in Virginia, according to updated reports from the local authorities and the media tallied by AFP.
Helene slammed into Florida late on Sept 26 as a Category 4 hurricane and surged north, gradually weakening but leaving a path of destruction.
Federal emergencies were declared in six states – Alabama, Florida, Georgia, North Carolina, South Carolina and Tennessee – with more than 800 personnel from the Federal Emergency Management Administration (Fema) deployed to assist local officials.
Repair crews were already at work on Sept 28, and the National Weather Service said conditions would “continue to improve today following the catastrophic flooding over the past two days”.
But it warned of possible “long-duration power outages”.
More than 2.7 million customers were still without electricity across 10 states from Florida in the south-east to Indiana in the Midwest as of the night on Sept 28, according to the poweroutage.us tracker website.
Helene originally slammed into Florida’s northern Gulf shore with powerful winds of 225kph. Even as a weakened post-tropical cyclone, it has wreaked havoc.
Record levels of flooding had threatened to break through several dams, but Tennessee emergency officials said on Sept 28 that the Nolichucky Dam – which had been close to breaching – was no longer in danger of giving way and people downriver could return home.
Massive flooding was reported in Asheville, in western North Carolina. Governor Roy Cooper called it “one of the worst storms in modern history” to hit his state.
Some residents in South Carolina – a state that is no stranger to hurricanes – said Helene was the worst storm to hit in 40 years.
There were reports of remote towns in the Carolina mountains without power or cellphone service, with their roads washed away or buried by mudslides.
In Cedar Key, an island city of 700 people off Florida’s Gulf Coast, the full destructive force of the hurricane was on view. Several pastel-coloured wooden homes were destroyed, victims of record storm surges and ferocious winds.
“I’ve lived here my whole life, and it breaks my heart to see it. We’ve not really been able to catch a break,” said Cedar Key official Gabe Doty, referring to two other hurricanes in the past year.
In South Carolina, the dead included two firefighters, officials said.
Georgia’s 17 deaths included an emergency responder, according to state officials.
Florida governor Ron DeSantis said the damage from Helene exceeded that of hurricanes Idalia and Debby, which both hit the same region south-east of Tallahassee in the last 13 months.
“It’s a real gut punch to those communities,” Mr DeSantis told Fox News.
In the Tennessee town of Erwin, a dramatic rescue operation unfolded, as more than 50 patients and staff trapped on a hospital roof by surging floodwaters had to be rescued by helicopters.
Remnants of the weakened storm dumped water over the lower Midwest on Sept 28.
In a statement on Sept 28, US president Joe Biden called Helene’s devastation “overwhelming”.
Mr Biden was briefed by Fema administrator Deanne Criswell and homeland security adviser Liz Sherwood-Randall on “the tragic loss of life across the region”, the White House said.
“The President directed them to continue to focus on how the Biden-Harris administration can speed support to impacted survivors and accelerate recovery efforts, including the immediate deployment of additional search and rescue teams into North Carolina,” it added.
Ms Criswell, who went to Florida on Sept 28 to survey the damage, will visit Georgia on Sept 29 and North Carolina on Sept 30 to assess the federal response to the storm’s impact.
September has been an unusually wet month around the world, with scientists linking some extreme weather events to human-caused global warming.