The National Hurricane Center is warning of an increasing risk of life-threatening storm surge and dangerous hurricane-force winds in Florida in the next two days.

In the Bahamas, Red Cross spokesman Matthew Cochrane said more than 13,000 houses, or about 45 per cent of the homes in Grand Bahama and Abaco, were believed to have been severely damaged or destroyed.

Governors in North and South Carolina, and Virginia have declared a state of emergency to give their states time to prepare for the possible arrival of the storm.