Hydrologists can't actually predict flood levels until the snow melts and the rivers start flowing.
But to help communities along the river plan for spring flooding the weather service provides a statistical model of possible river crests.
“We can't say, 'Whoops, we didn't think it was going to happen.' We have to buy the bus for the 5 o'clock rush hour.”Pat Zavoral
Computer models use weather data from each of the past 58 years, and according to Hydrologist Mike Lukes, they compare that data to current conditions.
"They run a scenario for each year so it give a range of what the model thinks the river could do during the outlook period," Lukes said. "So it is pretty much a planning tool and gives an idea of the range of river levels."
Lukes says heavy rains last fall left soils saturated. Models show a later than normal melt which could mean rapid runoff and higher river levels.
The new flood outlook says there's a 50 percent chance the river will reach 38.6 feet in Fargo. That would be the third highest flood on record, about a foot lower than the crest in 1997. That's the year when disastrous floods hit communities all along the Red River. The outlook comes as a surprise to Fargo City Administrator Pat Zavoral, who says he didn't think the river would rise that high this year because there's been much less snow this year than in 1997, the year of the record flooding.
"It's about half of what it was in '97 in terms of water content," Zavoral said. "But that wet fall seems to really throw a conundrum into how to approach this spring. So with that, we have to gear up to protect the city the best we can. We can't say, 'Whoops, we didn't think it was going to happen.' We have to buy the bus for the 5 o'clock rush hour."
The city will likely build some additional temporary earthen dikes and order more sandbags.
Zavoral says there's also concern about newly developed neighborhoods in south Fargo that could be hit by overland flooding.
Downstream from Fargo, Grand Forks, N.D. is protected by a massive levy system built after the 1997 flood. But officials there are considering adding clay to the top of permanent levy in some areas, as insurance against higher than expected river levels.