Sarah Liljestrand and her husband, Mike, background, look out from the back of a Minnesota National Guard truck as the couple is evacuated from their home that was overcome by Red River floodwaters Saturday in Oakport, Minn.

Fargo, N.D. ? Fargo’s fears of a catastrophic flood eased Saturday with word that the Red River apparently crested at lower-than-expected levels, and weary residents turned their attention to ensuring their hastily built levees hold up against an onslaught of ice-laden water expected to stay high for at least a week.

National Weather Service meteorologist Mike Hudson said the Red River began receding Saturday morning, surprising residents who were bracing for a crest today. But the river can still fluctuate up to a foot and may remain at dangerous levels for a week, meaning people will still have to wait several days before they are completely safe.

“The best news we can take from this is the river has crested,” Fargo Mayor Dennis Walaker said. “But diligence is going to have to be required for at least eight more days and hopefully things will continue to drop.”

Forecasters say the river is retreating because cold temperatures have been freezing water that normally would be flowing into the river. By the time that water thaws, the biggest flooding threat should have passed, Hudson said.

The weather service said the river crested around midnight at 40.82 feet. As of 5:15 p.m., it had dropped to 40.53, a significant shift from earlier forecasts that predicted the river would crest as high as 43 feet — the same level as the dikes protecting Fargo.

Despite the revised forecast, officials did not back down in their efforts to fend off the floodwaters, deploying high-tech Predator drone aircraft, calling up more National Guard troops and asking residents to form neighborhood dike patrols to look for any breaches in levees.

The flooding has forced hundreds of residents in the Fargo area from their homes and submerged basements and ground floors in an untold number of houses along the river.

Officials said they were increasing the number of National Guard troops from 1,700 to 1,850 and bringing in hundreds of large bags that hold a ton of sand and could be dropped by helicopter into breaks in the levees.

President Barack Obama assured the nation Saturday he was keeping close watch on the floods and putting the government’s full weight behind efforts to prevent disaster.