It was also the first time a Greek letter named storm made landfall in the continental U.S.
Forecasters say Tropical Storm Sally is expected to become a hurricane on Monday and reach shore by early Tuesday.
Officials in the New Orleans area issued a mandatory evacuation order for areas outside of levee protection.
Forecasts suggest the storm would reach hurricane strength early in the week before striking the northern Gulf Coast.
The president met with officials but no locals whose homes had been destroyed. He said Louisiana has "been a great state for me.”
It was one of the strongest hurricanes ever to strike the U.S.
The National Weather Service is warning residents to brace for "catastrophic damage."
The hurricane weakened as it moved inland to a Category 2 storm.
A Category 4 hurricane can cause damage so catastrophic that power outages could last for months in places.
The National Hurricane Center projected that Laura will become a Category 3 hurricane before landfall late Wednesday or early Thursday.