Hurricane Gustav has made landfall south-west of the city of New Orleans.
The eye of the storm crossed land near Cocodrie, in Louisiana, on Monday (3am on Tuesday NZT).
Shortly before that, Gustav was downgraded to a Category Two storm.
It has now weakened to a Category 1 hurricane.
Floodwaters splashed over a concrete wall at the New Orleans Industrial Canal, but the US Army Corps of Engineers said the levees had not yet been breached.
Nearly 2 million people fled the Gulf coast as Gustav approached - only 10,000 are believed to have remained in New Orleans.
Gustav earlier killed at least 86 people in the Dominican Republic, Haiti and Jamaica.
New Orleans last week marked the third anniversary of Hurricane Katrina which struck on 29 August 2005 and flooded 80% of the city. Some 1,500 people in five states were killed. The cost of the storm was $US80 billion.
Another hurricane has formed in the Atlantic Ocean.
Tropical storm Hanna has just been upgraded. It is centred near the Bahamas with winds of 120km an hour.
The US National Hurricane Center now predicts Hanna will track along the coast of Florida before making landfall at the end of the week in the state of South Carolina.