Louisiana on Wednesday declared a state of emergency as a storm in the Gulf of Mexico was fast developing into a category 1 hurricane and spinning towards the Louisiana coast. Experts are warning that the resulting storm surge could push the already swollen Mississippi River precariously close to the tops of levees that protect New Orleans – in what will be their greatest test since the catastrophic failure during Hurricane Katrina in 2005.
The latest dire forecasts come as the city was already reeling from flash flooding on Wednesday morning. Garbage containers tilted on their sides and pieces of wood floated down rain-swollen streets in a number of neighborhoods.
Water was up to the doors of many cars during the morning rush hour and a waterspout over Lake Pontchartrain was also spotted in the Gentilly neighborhood.
The mornings storms were associated with the broader area of disturbed weather over the gulf which forecasters now believe will organize and strengthen into a named storm – Barry – as it moved west through the Gulf’s warm waters.
Forecasters say parts of Louisiana could see up to 12in (30.5cm) of rain by Monday, with heavier amounts possible in some spots.
On Wednesday afternoon, Louisiana’s governor, John Bel Edwards, announced a state of emergency across the state that is effective until 8 August unless terminated sooner.
“This is going to be a Louisiana event with coastal flooding and widespread, heavy rainfall potentially impacting every part of the state,” Edwards said in a statement.
“No one should take this storm lightly,” he added. “As we know all too well in Louisiana, low intensity does not necessarily mean low impact.”
He encouraged residents to check their supplies and make emergency contingency plans.
The National Weather Service said New Orleans is protected to a river level of 20ft (6.1 meters), the same level that it is now forecasting the river to reach by Friday. That would mark the highest river level at New Orleans in nearly 70 years.
The river levels in Louisiana have been high for months due to flooding further upriver in the midwest. The army corps of engineers have been using spillways to divert the river’s flow since May.
This would be the highest crest on the Mississippi River at New Orleans since 1950.
Arguably, this is the city’s biggest test since Katrina. River levees are only built to 20ft, and have not been tested in this way in decades — if ever. This is a deadly serious situation. https://t.co/0VZwwdWFOf
Though much of the heaviest rain is not expected until the weekend, by mid-morning as much as 7in of rain had fallen over the metropolitan area. City officials urged residents off the roads, citing “widespread street flooding”, and had suspended all bus and streetcar services. Always at issue in the city, which mostly sits below sea-level, was the status of the 120 pumps used to push rainwater out of the streets. Officials said 118 are online, and that they were “all hands on deck” and “continuing to work this event”.