MIAMI (Dispatches) -- Millions of Florida residents were without power on Tuesday as the remnants of Hurricane Irma spun northwest into the southeastern U.S., drenching the region and causing rivers to overflow.
Most of the Sunshine State appeared to have dodged forecasts of catastrophic damage despite dire early warnings.
But Irma's overall death toll jumped to at least 40 after Cuba reported that 10 people had been killed there over the weekend.
Irma roared ashore as a powerful Category 4 hurricane when it hit the far southern Florida Keys on Sunday, tearing boats from their moorings, uprooting palm trees and downing power lines, after devastating a string of Caribbean islands.
By the time it hit the U.S. mainland the storm had been downgraded, and by late Monday it had weakened further to a tropical depression.
Across the Caribbean, hard-hit island residents struggled to get back on their feet as Britain, France, the Netherlands and the United States increased relief efforts.
French President Emmanuel Macron travelled to the region on Tuesday to tour devastated French territories, joining the Dutch king who had arrived in his country's Caribbean territories on Sunday.
In Florida, the damage in most cases was not as bad as feared.
"If this had been a Category 4 hurricane the whole scenario would have been completely different," said Bob Lutz, a 62-year-old business owner.
About 15 million people in Florida were without power, however, and Governor Rick Scott said the island chain known as the Keys had suffered widespread damage.
"It's horrible what we saw," Scott said after flying over the island chain aboard a Coast Guard helicopter. He said the water, electricity and sewage systems in the Keys were non-operational, and that trailer parks had been "overturned."
"We now go through the much longer phase, which is the recovery phase," said Miami Mayor Carlos Gimenez. "And believe me, folks, some of this is going to take a while, especially power restoration."
Most Keys residents evacuated from the low-lying tourist archipelago, known for its fishing, scuba diving and boating, before Irma struck.
The storm felled trees and left debris and vehicles strewn across the streets. But concrete homes appeared to have withstood the powerful gusts.
Authorities were allowing residents and business owners in the upper part of the Keys to begin returning on Tuesday.
"Returning residents should consider that there are limited services. Most areas are still without power and water. Cell service is spotty. And most gas stations are still closed," Monroe County authorities said in a Facebook post.
Heavy rain was a problem: Florida's northeastern city of Jacksonville, population 880,000, ordered urgent evacuations amid record flooding along the St Johns River.
Flooding was also reported in Charleston, South Carolina.
Irma had triggered orders for more than six million people to flee to safety, one of the biggest evacuations in U.S. history.
Before reaching the United States Irma tore through a string of Caribbean islands, going from tiny Barbuda on Wednesday to the tropical paradises of Saint Barthelemy and Saint Martin, the U.S. Virgin Islands, Puerto Rico, the Dominican Republic, Haiti and the Turks and Caicos Islands.
About 400 exhausted and traumatized hurricane survivors landed in France and the Netherlands on Monday aboard military planes.
Both the French and Dutch governments have been criticized for delaying their emergency response, and especially over the handling of looting on Saint Barthelemy and Saint Martin, the latter an island with both French and Dutch sectors.
Cuban officials said Irma was the deadliest hurricane to strike the island since Dennis in 2005, adding that three-quarters of the population was without power.
"This is a big warning already, when you know that climate change is getting more and more cruel," said Francisco Garcia, coach of Cuba's national karate team, whose home was damaged by Irma.