Chance for major flooding low, but more winter to come

While the Grand Forks-area has received around 30 inches of snow this winter, the chances for flooding this spring are not too high currently, the National Weather Service says.
A grain elevator in Drayton, ND, reflects on the flooded Red River at sunset in 1997. In the foreground, a plywood and sandbag reinforced dike protects the town from floodwaters. photo by J. Albert Diaz/Miami Herald

While the Grand Forks-area has received around 30 inches of snow this winter, the chances for flooding this spring are not too high currently, the National Weather Service says.

Any additional moisture would have an impact on the potential of flooding this spring, but snowfall hasn't been above normal, so major flooding is not too likely at this point, said Amanda Lee, service hydrologist with the weather service.

While the Grand Forks area has received more snow recently, for the most part the snowfall has been fairly dry, Lee said, noting that there is still a lot of winter left to go.

"It's not really a factor of how much snow you're talking about, it's how much moisture is in that snow," she said. "Every snowstorm is going to have different moisture content in the snow, so that is a big factor in it."

However, if the area continues to get hit with storms of 4 to 6 inches a couple of times a week the snow will start to add up, she said. Lee added the weather service will continue to monitor snowfall totals and its potential impact on flooding in the area.

The weather service also considers what river conditions were like at the beginning of winter when looking at flood potential. Rivers in the Grand Forks area were around normal levels at the beginning of winter, Lee said. In the southern part of the Red River Valley, river levels were slightly higher, she said.

Other factors include moisture levels in the ground already, as well as frost depth.

The area has experienced drier conditions over the past couple of years, which allows for the soil to be able to absorb more moisture.

Frost depth is around 35 inches, Lee said. The deeper the frost depth is, the longer it takes for the ground to thaw out, so something like spring rains on top of that frozen ground could increase the chance of flooding, she said.

Once spring arrives, the amount of rain and snow in the area could also add to the potential for flooding, as well as temperatures and how quickly snow is melting.

Some amount of flooding, especially near Oslo, Minn., and Fargo, is normal no matter what type of winter or spring the area has, Lee said. The area hasn't had major flooding since around 2009 or 2010.

For now the area is in a "wait-and-see" pattern as winter continues and spring approaches, she said. The weather service will put out another flood outlook later this month, which will take into account the latest snowfall totals and other information.