Roads have been flooded and people forced onto rooftops as Storm Barry dumped heavy rains on Louisiana.
Barry had been deemed a Category 1 hurricane but weakened to a tropical storm as it made landfall at Intracoastal City, about 160 miles west of New Orleans.
There were fears the rainfall would test the levees and pumps that were bolstered after Hurricane Katrina devastated New Orleans in 2005.
"This storm still has a long way to go before it leaves this state," Louisiana Gov. John Bel Edwards said on Saturday night.
"Don't let your guard down."
By early Saturday evening, New Orleans had been spared the worst effects, receiving only light showers and gusty winds.
A National Weather Service forecaster said the city may escape with only five to 10 centimetres of rain.
But officials warned that Barry could still cause disastrous flooding across a wide stretch of the Gulf Coast and drop up to 50 centimetres into Sunday across other parts of Louisiana.
Forecasts showed the storm on a path towards Chicago that would swell the Mississippi River basin with water that must eventually flow south again.
The Coast Guard rescued a dozen people from flooded areas of Terrebonne Parish, south of New Orleans, some of them from rooftops, a spokeswoman said.
The people included a 77-year-old man who called for help because he had about 1.2 metres of water in his home.
Nearly all businesses in Morgan City, about 85 miles west of New Orleans, were shuttered with the exception of Meche's Donuts Shop.
Owner Todd Hoffpauir did a brisk business despite the pounding winds and pulsating rain.
While making doughnuts, Mr Hoffpauir said he heard an explosion and a ripping sound and later saw that the wind had peeled off layers of the roof at an adjacent apartment complex.
In some places, residents continued to build defences against rising water.
At the edge of the town of Jean Lafitte just outside New Orleans, volunteers helped several town employees sandbag a 600-foot stretch of the two-lane state highway.
The street was already lined with one-ton sandbags, and 14-kilogram bags were being used to strengthen them.
"I'm here for my family, trying to save their stuff," volunteer Vinnie Tortorich said. "My cousin's house is already under."
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here