The eye of Hurricane Irma has hit Florida’s southern islands as a category four storm, forecasters say.
It is expected to pummel the low-lying Keys with winds reaching 130mph (209km/h), before travelling north-west up Florida’s Gulf Coast.
More than 6.3 million people were told to evacuate Florida, with warnings of a huge storm surge that would be “life-threatening” to anyone in its path.
Irma has already devastated parts of the Caribbean with at least 25 deaths.
Extreme winds, around the eye of the hurricane, are expected to last for the next two hours in the Lower Florida Keys area.
It is feared that a storm surge reaching 15ft (4.6m) could hit the islands, which all residents were ordered to leave.
Latest official figures said more than 400,000 homes in Florida lost power in the hours before Irma made landfall.