Chance for river flooding in Cedar Rapids this spring deemed small

The potential for spring flooding is below normal on the Mississippi River and slightly below normal on its Eastern Iowa tributaries, according to the National Weather Service's second spring flood outlook of the season.

The Weather Service's Quad Cities office based its prediction, issued Thursday, on current conditions of snowfall, snow moisture content, stream levels, soil moisture and frost depths.

Although snowfall has been slightly above normal this winter, the current liquid content of the snow cover is well below normal, the Weather Service said.

Both soil moisture and stream levels are slightly below normal and frost depths are near normal, the report stated.

'Any spring flooding that occurs will likely be driven by spring rain events,” the Weather Service said.

With above-freezing daytime high temperatures predicted for the week ahead, the Weather Service said the rapidity of the impending thaw will dictate how much of the snowmelt soaks into the soil and how much runs off into streams.

'If there is a rapid warm-up, the frost depth could interfere with the absorption of snowmelt and rainfall and increase the rate of runoff,” the Weather Service said.

A slow and prolonged thaw would result in more snowmelt infiltrating the soil and improving soil moisture deficits, the report said.

In Cedar Rapids, there is just a 7 percent chance the Cedar River will reach its 12-foot minor flood stage, according to the outlook.

The outlook predicted a less than 5 percent chance the Iowa River would reach its 22-foot minor flood stage in Iowa City.

Eastern Iowa's highest probability of flooding is in historically flood-prone Marengo, where there is an 87 percent chance the Iowa River will reach its 14-foot minor flood stage.

The Weather Service office in La Crosse, Wis., which covers much of northeast Iowa, said the lack of winter precipitation 'points to a very low likelihood” of flooding from snowmelt runoff.

As thick ice in streams breaks up, however, 'ice jams are a definite possibility” with the potential for localized flooding, the La Crosse office said.