Hurricane Wilma has swept over Florida after hitting the coastline near the city of Naples on Monday morning.
The category three storm had winds of 125mph (200km/h) and heavy rains as it struck at about 6.30am local time.
At least 17 people across the Caribbean have died as a result of the hurricane - which at one point was measured as the strongest ever on record.
The storm has flooded large parts of Florida's Key West and has left 300,000 homes in the area without power.
"This is a very dangerous hurricane," National Hurricane Centre director Max Mayfield said.
The eye of the storm - the inner core of the hurricane - is estimated to be 60m (96km) wide.
At the weekend, Hurricane Wilma hit Mexico's Yucatan coastline and heavy rain and strong winds are buffeting Cuba.
Another tropical storm called Alpha has formed in the Caribbean, meaning 2005 is the busiest hurricane season on record.
It takes the number of storms named in the Atlantic to 22 this year.
Forecasters have used up all the names planned for storms this year and have now moved from the standard alphabet to the Greek alphabet - something they haven't done for almost 60 years.
The hurricane season still has five weeks left to run before it finishes at the end of November.