Idalia on Thursday evening developed into a post-tropical cyclone as it veered away from the US East Coast after ploughing through Florida, Georgia and the Carolinas with significant rain.
The National Hurricane Centre issued a tropical storm watch for Bermuda since the storm, right off the shore of North Carolina's coast, still featured maximum sustained winds of 100kph.
The storm has continued to weaken since crashing into Florida as a Category 3 hurricane on Wednesday.
North Carolina Governor Roy Cooper warned residents to prepare for heavy rainfall and flooding. In Charleston, South Carolina, a surge from Idalia brought flooding to streets and neighbourhoods.
The high tide reached 2.8 metres, the fifth-highest reading in Charleston Harbour since 1899.
Florida and Georgia residents living along Idalia's path of destruction picked through piles of rubble where homes once stood, threw tarps over ripped-apart roofs and gingerly navigated streets left underwater or clogged with fallen trees and dangerous electric wires.
President Joe Biden spoke to Florida Governor Ron DeSantis and promised whatever federal aid is available.
He also announced that he would go to Florida on Saturday to see the damage himself.
The President used a news conference at the Federal Emergency Management Agency's headquarters to send a message to Congress, especially those politicians who are balking at his request for $12 billion in emergency funding to respond to natural disasters.
“We need this disaster relief request met and we need it in September” after Congress returns from recess, said Mr Biden, who had pizza delivered to Fema employees who have been working round the clock on Idalia and the devastating wildfires on Maui, Hawaii.
In Florida, officials and 5,500 members of the National Guard began search-and-recovery efforts. They also inspected bridges and cleared debris.
The event was unprecedented for many places dotted around the Big Bend coast, which was hit with 201kph winds.
No hurricane-related deaths were officially confirmed in Florida, but the state’s motorway patrol reported two people had been killed in separate weather-related crashes hours before Idalia made landfall.
Insured property losses in Florida were expected to reach $9.36 billion, UBS estimated.
Cedar Key was one of the areas hardest hit by the hurricane after it made landfall. Video footage shared by Cedar Key Fire and Rescue showed roads inundated with floodwaters. The back side of the island was also shut off.
Idalia was the strongest hurricane to hit Florida since last September when Category 4 Hurricane Ian killed 150 people and caused more than $112 billion in damage.
Mr Biden approved an emergency declaration in anticipation of the storm, freeing up federal resources for recovery efforts.
Drone footage shows aftermath of Hurricane Idalia in Florida
“There will be a lot of debris from this storm. There's going to be a need to have all hands on deck to be able to do,” he said.
Mr DeSantis said the state's transport department had hundreds of heavy equipment vehicles to help clear the debris. The state has also secured 1,100 generators.
As many as a half million customers were without power at one point in Florida and Georgia as the storm ripped down utility poles.
More than 30,000 utility workers were looking to repair downed power lines that left hundreds of thousands without electricity. The state also called up hundreds of search and rescue personnel ahead of the storm.
US oil company Chevron evacuated staff from three oil production platforms while Kinder Morgan planned to shut a petroleum pipeline.
The storm passed over Cuba on Monday night. Residents evacuated towns as up to 10cm of rain were recorded but no deaths were reported.
