Tropical Storm Barry, currently circulating in the Gulf of Mexico south of New Orleans, is heading for the shore and approaching hurricane speeds, threatening to dump torrential rain on the city and cause dangerous flooding in conjunction with the swollen Mississippi River.
The National Hurricane Center’s director, Ken Graham, said people should be concerned even if Barry comes ashore as a tropical storm instead of a hurricane because its slow movement will bring hazardous amounts of rain either way.
Forecasters said there’s still a chance Barry will briefly strengthen to a hurricane as it comes ashore.
While many New Orleanians shrugged on Thursday at the prospect of the storm reaching no more than hurricane category 1, if that, the authorities had warned that the threat of flooding was serious, more so than sheer wind speeds.
The influx of water from the ocean and the river pose the biggest threat to the levees that protect New Orleans since the catastrophic and fatal effects of Hurricane Katrina in 2005.
Pockets of Louisiana, where hurricane warnings are in effect, could get rainfalls as high as 25in (63cm).
The National Hurricane Center said the center of the storm was about 95 miles (155km) south-west of the mouth of the Mississippi River on Friday morning and its top winds were blowing at 50mph (85kph).
Louisiana and New Orleans itself are under a state of emergency and there is a flood watch along the coast in Mississippi.
With the Mississippi River at unusually high levels for the beginning of the annual summer hurricane season, concerns are raised that the deluge, coupled with a storm surge, could stress the levees that ring New Orleans. New Orleans sits below sea level.
Forecasters now predict Barry will add up to 3ft to a river already 19 feet above sea level in some places.
The confluence of a storm and a high river has led to preparations by the US army corps of engineers who have begun shoring up low areas in the levee system built to keep the Mississippi from bursting its banks after a devastating flood in 1927.
Even in the event that the river comes over the top of the levees, officials said, it will probably cause flooding, but not a catastrophe breach.
“We’re confident with the integrity – the levees are extremely robust and designed to handle a lot of pressure,” corps spokesman Ricky Boyett told Nola.com.
