Hurricane Nicole hit Florida on Thursday with 70mph (110kph) winds but has been downgraded to a tropical storm after it slowed on making landfall.
States of emergency remain and evacuation orders are in place, with heavy rain and storm surges forecast.
Nicole has already lashed Grand Bahama Island as a huge category one hurricane, with the scale of the devastation not immediately clear.
Storms of this size so late in the year are extremely rare. After Florida, Nicole is set to hit Georgia and South Carolina.
November hurricanes are rare in Florida. Since record-keeping began in 1853, the sunshine state has been hit by only two: in 1935 and 1985.
Nicole comes just weeks after Hurricane Ian hit Florida, leaving more than 100 people dead. More than 100,000 customers have been left without power by the storm.
The National Hurricane Center (NHC) upgraded Nicole on Wednesday evening from a tropical storm, then downgraded it again an hour after it made landfall and slowed.
Forty-five of the state's 67 counties are under a state of emergency and four counties are under mandatory evacuation orders.
Nicole's late arrival follows a relatively quiet storm season - for the first time since 1997 not a single hurricane or tropical storm formed in the Atlantic basin this August.
The arrival of Nicole is also expected to further disrupt a long-delayed Nasa rocket launch, which aims to bring Americans one-step closer to returning to the Moon.