Forecasters say the revised level — down from last week's minimum of 38 feet and a maximum of 42 feet — is due mostly to an ideal melt cycle and the lack of significant precipitation, although heavy rain is possible early next week.
Fargo officials said they are scaling back flood protection efforts after the National Weather Service on Wednesday lowered the crest prediction on the Red River, but promised that decisions won't be based on saving money.
The updated forecast shows next week's likely crest in Fargo and Moorhead, Minn., ranging between 38 and 40 feet, down a couple of feet from earlier predictions. The river overflows its banks at 18 feet, but most structures in the city are protected without additional measures to about 38 feet.
Each additional foot of flood protection past about 37 feet costs the city about $1 million. When the Red River gets up to 38 feet, Fargo needs to build dikes for 117 homes; at 40 feet, dikes are needed for a total of more than 200 homes.
Fargo Mayor Dennis Walaker said the city will prepare for 40 feet.
"I think the focus should be on whether we win or lose. Right now we're in a winning mode," Walaker said Wednesday at a public briefing. "We'll worry about the spending later."
Greg Gust, an NWS meteorologist, said water has been parked over a large part of the southern Red River Valley for several days. Ditches are full and ready to overflow in many areas, he said.
"The rapid warm-up expected from Thursday into next week should break all of this loose," Gust said.
Forecasters say the revised level — down from last week's minimum of 38 feet and a maximum of 42 feet — is due mostly to an ideal melt cycle and the lack of significant precipitation, although heavy rain is possible early next week. The 40-foot mark takes into account the possibility of localized thunderstorms and the potential for 1 to 2 inches of rain.
The updated model has also lowered the expected crest in Wahpeton, about 50 miles upstream of the north-flowing river, to 15 feet on Monday. Last week's forecast called for a 17-foot flood.
Fargo officials say there's still work to be done to protect properties, but the updated prediction reduces the number of needed sandbags from about 1.5 million at 43 feet to about 100,000 at 40 feet. It would also cut down on the number of volunteers needed to help. Fargo high school students had been scheduled to start placing sandbags Thursday, but that has been pushed back to Friday.
Fargo shut down its sandbag filling operations at 4 p.m. Wednesday, after producing more than 600,000 bags in five days. That gives the city more than 2 million bags in reserve.
It's the fourth major flood fight in five years for the area, beginning with a record-setting flood of just under 41 feet in 2009. That was followed by the seventh highest flood on record in 2010 and the fourth-highest crest in 2011. Residents enjoyed a mild and dry winter and spring in 2012.
While Fargo Deputy Mayor Tim Mahoney called the lower forecast a "slight relief," Cass County officials said it did little to alter their plans. They are building at least one mile of clay levees and have delivered 100,000 sandbags, at least two-thirds of which will placed be around homes, county engineer Jason Benson said.
"It really didn't change much for us," Benson said. "We have so many areas that are isolated by high water that we need to get the sandbags out before the rivers start rising."