Some schools closed in "an abundance of caution" after Mayor Mitch Landrieu announced that one of five turbines that help power "a majority" of the city's oldest and most powerful drainage pumps was damaged overnight in a fire. Three of the five already were offline, in need of repairs.
With the main source of power to many of those pumps -- the ones in the oldest neighborhoods east of the Mississippi River -- now severely reduced, the flood risk from an ordinary rainstorm has spiked.
"We feel it is better to be safe than sorry," New Orleans Superintendent Henderson Lewis Jr. said.
The turbine breakdown comes just days after "a couple hundred" New Orleans properties flooded in weekend storms. Officials have acknowledged that six of the city's most powerful pumps were not in service in hard-hit areas, though some city leaders first said the drainage system was "operating at its maximum capabilities."
Those six pumps are still offline, along with two similar ones several miles away, a city official told CNN.
The latest breakdown, Landrieu said Thursday, "is affecting our draining capacity even further."
Residents advised to stay indoors, off roads
City employees had been "working around the clock" to ready key equipment in advance of a storm system expected to move in starting Thursday night. Still, Landrieu and his deputies advised residents to "remain indoors during heavy rainfall" in the coming days.
Residents also are advised to stay off the roads unless "an emergency makes it absolutely necessary to do so," the mayor's office warned in a statement.
New Orleans could receive 2 inches of rain over the next three days, which could lead to flooding, depending on how fast and hard it falls, CNN meteorologists predict. Scattered showers and thunderstorms are due to push in Thursday night, with "numerous" showers and thunderstorms and a 60% chance of rain on Friday and Saturday, according to the National Weather Service.
Pumps unavailable as rain poured
Because of New Orleans' unusual topography -- with many areas below sea level -- it takes about 100 pumps, some as big as a garage, spread across every neighborhood to suck water out of storm drains and canals and push it into a nearby lake or other water bodies. In most other cities, gravity does the work of moving rainwater into drainage basins.
"It should have never happened like this," Circle Food Store Manager Dwayne Boudreaux told CNN affiliate WDSU
, adding that Saturday's rain simply didn't have anywhere to go. "It's killing my business. It's hurting my customers. I am going to have to be closed. I am hoping I can open up next week."
In light of Saturday's drainage problem, Landrieu requested the resignation of four top officials. A spokeswoman for Landrieu told CNN he asked for the resignations of General Superintendent Joe Becker, Communications Director Lisa Martin, and Department of Public Works Director Mark Jernigan. Sewerage and Water Board Executive Director Cedric Grant was not asked to resign but submitted his retirement letter.
Landrieu, a Democrat who is president of the US Conference of mayors, is hosting his fellow municipal executives this weekend in New Orleans for their summer meeting.