People in Florida have been feeling the first effects of Tropical Storm Isaac as it nears the US coastline.
After lashing the Florida Keys overnight there, Isaac is now heading towards the northern Gulf Coast, the BBC reports.
The National Hurricane Center says the storm is expected to turn into a hurricane when it crosses the coastline.
Louisiana, Mississippi and Alabama have followed Florida in declaring states of emergency.
Hundreds of flights have been cancelled and oil and gas production is affected by the storm, which has already killed at least nine, including eight in Haiti.
Low-lying areas to the north of the Gulf of Mexico are on flood alert.
Workers on oil and gas drilling platforms are being evacuated, as are residents of low-lying coastal areas.
Residents of the Florida Keys have been driving north all weekend. The BBC reports they are well-used to the ritual of storm preparation.
Florida Governor Rick Scott issued the declaration on Saturday to ensure emergency services would be ready when the storm arrived.
Florida has already been drenched by heavy rains and strong winds from the storm, and hundreds of flights are cancelled at Miami and Fort Lauderdale airports.
A hurricane watch has been extended westward to include New Orleans, which was devastated by Hurricane Katrina on 29 August, 2005, killing more than 1800 people and causing billions of dollars of damage.