Hurricane Isaac has made landfall in the United States.
The category one hurricane has crossed the coast just a day short of the anniversary of Hurricane Katrina, that devastated New Orleans in 2005.
Isaac is expected to cause significant damage and flooding in the gulf states of Louisiana, Mississippi, Alabama and Florida.
President Barack Obama says authorities are bracing for the worst.
"I want to encourage all residents of the Gulf Coast to listen to to your local officials and follow their directions, including if they tell you to evacuate."
President Obama says federal authorities are on standby to help.
"As President I'll continue to make sure that the Federal Government is doing everything possible to help the American people prepare for and recover from this dangerous storm."
Photp: Getty Images