Hurricane Hermine has barrelled ashore in Florida's Big Bend, killing one person, raising a storm surge that destroyed beachside buildings and bringing heavy rain and tens of thousands of power outages.

The first hurricane to hit the state in more than a decade toppled trees in the state capital of Tallahassee and downed power lines and injured people in their homes.

Hermine later weakened from its peak wind speed of 80mph to a tropical storm as it moved into southern Georgia. The storm is expected to move into the Carolinas and up the East Coast with the potential for drenching rain and deadly flooding.

A homeless man in Marion County, south of Gainesville, Florida, was killed when he was hit by a tree as the storm moved through, governor Rick Scott said at a news conference.

At Florida's Dekle Beach, just south of the state's Big Bend where the peninsula meets the Panhandle, a storm surge damaged numerous homes and destroyed storage buildings and a 100-yard fishing pier. It is about 60 miles south east of St Marks, where Hermine made landfall.

An unnamed spring storm that hit the beach in 1993 killed 10 people as most residents refused to evacuate. This time, only three residents stayed behind. All escaped injury.

At nearby Keaton Beach, about two dozen people waited on a road just after sunrise trying to get to their homes. Police had the road blocked because of flooding. Taylor County Commissioner Jody DeVane said several homes were damaged.

High winds knocked trees on to several houses in Tallahassee, injuring residents inside, fire and rescue spokesman Mike Bellamy said. He added that an unknown number were taken to area hospitals with injuries that were not thought to be life-threatening. Mr Bellamy said his agency responded to more than 300 calls overnight. Mayor Andrew Gillum estimated as many as 100,000 area residents were without electricity on Friday morning.

In Pasco County, north of Tampa, authorities said flooding forced 18 people from their homes in Green Key and Hudson Beach. Pasco County Fire Rescue and sheriff's deputies used high-water vehicles to rescue people from rising water. The Sunshine Skyway Bridge that spans Tampa Bay was closed because of high winds.

In Wakulla County, south of Tallahassee, at least seven homes were damaged by falling trees, said Scott Nelson, the county's emergency manager.

As Hermine moved north, Georgia Power estimated about 19,000 homes and businesses were without power state-wide. Many of those were in Valdosta and surrounding Lowndes County, about 15 miles north of the Georgia-Florida border. Lowndes County spokeswoman Paige Dukes said crews were dealing with fallen trees and snapped power lines, but no injuries had been reported. Winds exceeding 55mph had been recorded in the county, with 4in to 5in of rainfall, she said.

The last hurricane to strike Florida was Wilma, a powerful Category 3 storm that arrived on October 24 2005. It swept across the Everglades and struck heavily populated south Florida, causing five deaths in the state and an estimated 23 billion dollars in damage.

Mr Scott earlier declared an emergency in 51 counties. He said 6,000 National Guardsmen were poised to mobilise for the storm's aftermath. The governors of Georgia and North Carolina also declared states of emergency.

AP