The weather forecast says the torrential rain that deluged streets in New Orleans is going to slacken Tuesday, a day after businesses were stopped, schools closed and areas flooded still recovering from Hurricane Katrina.
Only a few showers were in the forecast.
"The heavy rains have passed by," National Weather Service meteorologist Jim Vasilj said.
The city's drainage pumps were working properly Monday but were unable to keep up with the intense rain, emergency preparedness officials said. They urged motorists to stay off roads.
In some areas, more than two inches (5 centimeters) of rain fell in an hour, while the city's pumps can handle only a maximum 1 inch (2.5 centimeters) in the first hour of a rainfall and 1/2 inch every hour thereafter, said Robert Jackson, a spokesman for the New Orleans Sewerage and Water Board.
"We just have to continue to work with our neighbors until we can develop a greater pump capacity," said Col. Terry Ebbert, director of Homeland Security for the City of New Orleans.
Mayor Ray Nagin shut City Hall early and schools across the city closed. Many of the businesses that were soaked had recently reopened after being damaged by 2005's Hurricane Katrina.
Making problems worse in New Orleans were catch basins clogged with debris from gutted or renovated homes. Jackson urged residents to clean out the basins to help in draining standing water from streets.
Meanwhile, officials closed a gate on the Harvey Canal in suburban Jefferson Parish where the waters threatened to top the walls. It was one of several in the area placed under new safety guidelines after Katrina's waters breached two New Orleans canals, causing catastrophic flooding.
The corps has worked to strengthen the canal, about five miles from downtown New Orleans, but engineers worried that water being driven into it might lead to flooding. The area around the canal includes homes and businesses.
Moisture from the Gulf of Mexico, ahead of a strong cold front, sparked the swift and strong rainfall that blanketed the area. Bob Wagner, a forecaster with the Slidell office of the National Weather Service, said the rain should slowly diminish Tuesday and bring with it cooler temperatures.
Despite the flooding potential, the rain also offered relief to parts of Louisiana that have been abnormally dry and to other drought-stricken areas of the Southeast.