President Donald Trump has declared a state of emergency in Louisiana as a growing tropical storm nears landfall.
Storm Barry has been gathering speed over the Gulf of Mexico in recent days.
Officials say sustained wind speeds have grown to 50mph (80km/h) and may still reach hurricane strength by the time it makes landfall.
It is expected to bring a storm surge and heavy rainfall to the city of New Orleans – which has already seen thunderstorms and flash floods.
The National Weather Service warns that flooding from the slow-moving storm poses the greatest risk.
Between 10-20in (25-50cm) rain is forecast to hit the state, where the Mississippi River is already nearing flood levels.
The president’s declaration frees up wide-ranging federal resources which can be used to help in the emergency situation.
Sea levels have also increased as a result of global heating, so if winds are blowing towards shore, this makes flooding much more likely during high tides.
If sustained winds from the storm exceed 74mph, Storm Barry will be declared a hurricane and become the first of the 2019 Atlantic season.
How is Louisiana preparing?
Officials have ordered thousands of residents in some low-lying areas to evacuate.
Mayor of New Orleans, LaToya Cantrell, has not issued a city-wide evacuation order because it is not a category three hurricane or above.
“This is going to be a major rain event across a huge portion of Louisiana,” he said on Thursday.
“Look, there are three ways that Louisiana floods: storm surge, high rivers and rain. We’re going to have all three.”
She, and other city officials, asked people to bring in their rubbish bins and clear gardens and streets in order to prevent debris from choking street drains and gutters or becoming airborne “projectiles”.