Hurricane Dennis has roared through north-west Florida and the Alabama coastline, knocking out power lines but causing less damage than first feared.
Dennis came ashore in the same region as Hurricane Ivan last year
Roofs went flying and trees fell as the winds hit, but the devastation of last year's Hurricane Ivan was not repeated.
Some 1.4 million people were told to leave their homes ahead of Dennis, which killed 21 in Cuba and Haiti.
Florida, Mississippi and Alabama have been declared disaster zones, allowing them to receive emergency federal aid.
The storm cut power to half a million homes and businesses, with some told it could be three weeks before supply is restored.
Dennis has been downgraded to a tropical storm as it moves inland but forecasters warn it could still be dangerous, bringing strong winds, heavy rains and possibly tornadoes.
It is expected to travel north from Mississippi through Tennessee, Illinois, Kentucky and Indiana.
Meanwhile the clean-up operation has begun behind it, with thousands of National Guard troops deployed in Florida, state officials said.
Recovery efforts are focused on clearing debris, assessing the damage to buildings, handing out emergency supplies and restoring power.
Florida governor Jeb Bush warned that many of those forced to live in temporary homes since Ivan hit might again be the worst affected.
"A lot of people are going to hurt, particularly the hundreds of thousands who live in trailers," he said.
But the predominant message was one of relief that the storm had not caused the same scale of devastation as Hurricane Ivan 10 months earlier.
'Dodged the bullet'
It made landfall at 1525 (1925 GMT) on Sunday with a storm surge of up to 4.6m (15ft) near Pensacola Beach, Florida.
"There has been some storm surge, some roof damage to homes, but it's nothing like we had during Hurricane Ivan," said Jenny Malden, emergency manager at the naval air station in Pensacola.
"We dodged the bullet on the most part although our beach has suffered badly again," said Sara Comander, a spokeswoman for Walton County, east of Pensacola, speaking to AP news agency.
Several houses and apartment buildings were badly damaged on Holiday Isle, offshore from Destin, an emergency management spokeswoman in Okaloosa County, Florida, told the Reuters news agency.
"There is a lot of infrastructure damage. One house, a nice one, is in the Gulf now," Kathleen Mitnacca said.
One man was electrocuted in Fort Lauderdale, Florida, after stepping on a cable brought down by the winds, AP news agency reported.
Nick Zangari, a restaurant owner in Pensacola, told AP: "We were hearing like explosions that must have been like air condition units from other buildings smashing to the ground... There were parts of buildings and awnings all around."
The storm has already left a trail of destruction behind it.
At least 10 people, including an 18-day-old baby, are known to have died when the hurricane approached the southern coast of Cuba on Friday.
More than 500,000 Cubans were moved from the path of the hurricane, which damaged buildings and knocked out power.
On Thursday, the hurricane thrashed the Dominican Republic and southern Haiti, where at least 11 people died when rivers burst their banks, flooding homes, and roofs were torn off buildings.
Dennis is the Atlantic's first hurricane this year and is the strongest to form in the Atlantic this early in the season since records began in 1851, the US National Hurricane Center (NHC) in Miami said.
It has proved less destructive in the US than feared because it is more compact and faster moving than Hurricane Ivan, which claimed more than 100 lives in the Caribbean and the US last September.