March 25, 2009 -- North Dakota is in a race against time as residents try to shore up huge sandbag levees ahead of massive flooding expected to hit this weekend. Forecasters predict the Red River's waters will crest at 41 feet by early Saturday, exceeding record levels set in 1997.

Along the river, residents engaged in a frantic battle against the fast-rising water and bitter cold. Water reached 35.6 feet in Fargo by midday Wednesday, according to the National Weather Service. City officials said they'll add another foot to the dikes -- already 42 feet high -- in an effort to withstand the river's crest.

Mayor Dennis Walaker said the city is bracing for the worst. "We're talking about levels never reached before by any stretch of the imagination," he said.

A 41-foot crest in Fargo would be two feet higher than the record level of 39.6 in April 1997, when the area was struck by one of the largest and costliest floods in U.S. history. President Obama has already declared the state a federal disaster area.

Downstream from Fargo in Oxbow, the Missouri River showed its muscle when icy floods burst levees and swallowed homes. Rescuers in airboats pulled stranded residents to safety.

"It was terrifying," said one resident who was rescued by officials today. "The water wasn't that deep this morning and we woke up, we got to the window… and there was the river... just right there."

In Bismarck, demolition crews used explosives to blast through an ice jam in the Missouri River, whose waters threatened low-lying regions of the city. Blizzard conditions and more than 8 inches of snow heightened the alert, where about 1,700 residents were forced to evacuate.

In Fargo, where three swollen rivers converge, it's been all hands on deck. Thousands of volunteers from across the state worked around the clock, building a 12-mile fortress of millions of sandbags to hold back the water Wednesday.

"The water's coming up, the snow's coming down, the rain is coming down… it's crazy," said Eric Lorenz, a sandbag volunteer, who waded through six inches of snow.

Volunteers Scramble With 48 Hours Left to Sandbag

Local universities and high schools cancelled classes to lend manpower to the city for the sandbagging effort.

"They're in need of students and anyone else who can work," said Karl Underdahl, a college student. "We're here working."

Volunteers who descended to build walls on Fargo resident Ilene Lee's riverfront back yard were greeted with pork sandwiches and tortilla soup. "We hope by feeding them good, they'll come back here and work hard," Lee told ABC News.

Capt. Dave Todd of the Fargo Police Department worries plunging temperatures could compromise the sandbags' effectiveness, which the city is counting on.

"If we leave them sitting outside for too long, they become like blocks of concrete and they're hard to work with, and they don't really work for flood protection at that point," Todd said.

Fargo residents have 48 hours to add a foot to the wall of sandbags surrounding the city, giving the city minimal time to prepare. In case the walls don't hold, officials have discussed and will distribute evacuation plans to resident on Thursday.

The Associated Press contributed to this report.