Video shows intense winds and flooding as residents hunkered down amid official warnings of its threat to life. Already, 3,000 homes in Louisiana have lost power.
Thousands have evacuated but those who remain have been told to take shelter and store enough food to last until it passes.
The National Weather Service (NWS) warned New Orleans residents to hide indoors.
“Go to an interior room or a small room with no windows,” the NWS tweeted.
“Stay put during this time.”
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“Wind gusts are picking up in Houma, Louisiana. Eyewall coming soon,” Mike Theiss, National Geographic reporter, said in a Tweet, referencing the centre point of the storm.
Another video shows an entire tree being uprooted before falling onto a home.
An National Weather Service statement warned parts of Louisiana may be “uninhabitable for weeks or months”.
President Joe Biden has said that it may take weeks to restore supplies.
President Biden said the Federal Emergency Management Agency (FEMA) has deployed 500 response personnel in Texas and Louisiana on Saturday in anticipation.
“We’ve prepositioned food, water, generators and other supplies in the area,” Biden said at a briefing with the FEMA.
“Power restoration and mobile communications support teams are also en route.
“We’ve also closely coordinated with the electric utilities to restore power as soon as possible.”