Hurricane Helene prompts mass evacuations in Florida as it nears landfall

Parts of Florida face "unsurvivable" conditions when Hurricane Helene hits later Thursday, the US weather service said, warning that howling wind will drive destructive waves and storm surge as high as 20 feet (six meters) onto the low-lying coast.

Residents heeded mass evacuation orders and fled ahead of the incoming hurricane -- projected to be one of the largest Gulf of Mexico storms in decades.

The fast-moving and intensifying storm was at Category 2 mid-day Thursday, the National Hurricane Center (NHC) in Miami said, packing wind speeds of 105 miles (169 kilometers) an hour as it churned over the gulf's warm waters.