Storm Barry has hit the US, with 70mph winds and heavy rain leading to 'life threatening' floods.
Although the storm was downgraded from a hurricane, Barry has still been causing chaos since it made landfall in Louisiana tonight.
Residents have been ordered not to travel unless absolutely necessary, with tornado warnings issued by local authorities.
About 400 people living along a Louisiana highway have been ordered to evacuate their homes, after multiple reports of levees overtopping in the parishes of Terrebonne and Plaquemines.
And all of Morgan City - home to more than 12,000 people - is currently without power, according to nola.com.
State Police posted on Twitter to reminded people not to travel unless absolutely necessary.
The post read: "As night falls and the severe weather continues across Louisiana, Troopers are stressing to drivers not to travel unless absolutely necessary.
"Remember to watch for downed trees and power lines. One should always assume that a fallen power line is live."
New Orleans, Baton Rouge and Lafayette areas are expected to feel the effects of Barry late into Saturday night through Sunday, according to the latest forecast.
National Weather Service New Orleans issued a tornado warning until 9.45pm local time as a band of heavy rain battered the region.
The National Hurricane Center, which had labelled Barry the first Atlantic hurricane of 2019 just hours earlier, said the storm came ashore near Intracoastal City in Louisiana with 70mph winds.
The NHC expects a further weakening to a tropical depression on Sunday as Barry moves inland at around 40mph.
Louisiana Governor John Bel Edwards warned residents not to take the storm lightly, but adding that the state and levees in New Orleans were ready for impact and should withstand the floodwaters.
He wrote in a post on Twitter Saturday: "There have been NO levee failures in Plaquemines Parish.
"There are isolated issues of flooding that state and local officials anticipated and are actively addressing."
Becky Broussard, homeland security director for Vermilion Parish, said the lone road leading to the town had flooded as Barry made landfall at Intracoastal City on late Saturday morning, it is reported.
She said: "We're still not out of the woods yet."
She added the parish is moving all emergency vehicles, including 15 fire engines, to higher ground to ensure they're safe from flooding.
The Mississippi River crested on Friday night in New Orleans at just under 17ft (5.18 meters), the National Weather Service said, much lower than a prediction earlier this week of 20 feet (6.1 meters), near the height of the city's levees.
The river was expected to surge again to about 17ft on Monday, the weather service said.
Streets and businesses were flooded along Lake Pontchartrain in Mandeville, just north of New Orleans, according to a Reuters witness.
President Donald Trump declared a state of emergency for Louisiana on Friday, freeing up federal disaster assistance if needed.
Authorities had urged New Orleans residents to secure property, stock up on provisions and shelter in place.
Some chose to flee the city, and tourism officials reported an exodus of out-of-town visitors on Friday.
The New Orleans Airport said all flights in and out on Saturday had been cancelled but most airlines were planning to resume operations on Sunday, weather permitting.