(CBS/AP) Isaac is passing over the mid-Mississippi and lower Ohio Valleys bringing threats of heavy rain and isolated tornadoes.
To the south, flood waters are receding. Hundreds of homes and businesses remain flooded and hundreds of thousands of people are without electricity.
The storm is blamed on at least seven U.S. deaths - five in Louisiana and two in Mississippi.
Now comes what is certain to be an expansive and long cleanup.
Isaac touched down in Louisiana on Wednesday and lingered over the Plaquemines Parish state for days.
Much of Isaac's remnants have tracked out of Arkansas, which received three to six inches of rain, but National Weather Service senior forecaster Brian Smith said thunderstorms from the outer bands of the storm system could affect the northern half of the state on Saturday.
The storm knocked out power to thousands of people in Arkansas, and Ohio hotel operators said their holiday weekend business was already taking a hit as families canceled planned outings to theme parks.
The storm cut power to 901,000 homes and businesses in Louisiana alone, or about 47 percent of the state, but that was down to fewer than 620,000 by late Friday.
More than 15,000 utility workers began restoring power to customers there and in Mississippi, but officials said it would be days before power was fully restored.
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LaPlace resident Roshonda Girrad was staying in a state-run shelter in Alexandria, 200 miles from her home. She was waiting for the chest-deep waters in her neighborhood to recede.
The massive, beige, windowless shelter next to Louisiana State University's Alexandria campus is currently home to almost 1,600 evacuees who either drove themselves or were bused in from various parishes inundated by rain from Isaac and the rising water from Lakes Pontchartrain and Maurepas.
"The showers are horrible. The food is horrible," Girrad said. "I'm not from around here. I don't know what's going on. We're in the dark."
As the Labor Day holiday weekend got under way, so did what was certain to be a long, slow recovery for Louisiana.
Motorists ventured out as power came back on and businesses reopened, clogging intersections with no traffic lights and forming long lines at gas stations. The Mississippi River opened to limited traffic, and in New Orleans, the normally lively French Quarter awoke from its nearly weeklong slumber.
Isaac dumped as much as 16 inches of rain in some spots, and about 500 people had to be rescued by boat or high-water vehicles. Thousands remained in shelters late Friday. At least seven people were killed in the storm in Mississippi and Louisiana.
