'Just be prepared': Iowa rivers at increased flood risk thanks to wet fall, increasing snowpack

Several Iowa rivers have an increased risk of flooding this spring, according to projections from the National Weather Service. 

Recently released NWS reports detailing flood expectations outline concerns about snowpack, high soil moisture and elevated streamflows. Jeff Zogg, a hydrologist with the National Weather Service in Des Moines, said the projection does not mean heavy flooding is certain to happen, but the signs are there.  

"Just be prepared for the possibility of flooding this spring," he said. "If people don't have flood insurance, there is a 30-day waiting period for flood insurance. That's the one thing to take into account.

"It's not something that you can buy and it takes effect the next day, so that's something to consider if they don't have it already." 

Zogg also said ground frost is deeper than usual due to a wet fall and long-lasting cold spells preceding February snow storms. Frost is 4 inches deep throughout much of the state and up to 2 feet deep in the northern and northeastern part of the state. This adds moisture to the soil, increasing flood chances.

Right now, the most concern is for the area surrounding the Mississippi River. 

"The probability for flooding is very high for at least minor flooding along the Mississippi River and most tributary rivers across eastern Iowa, northwest and west central Illinois, and northeast Missouri," a weather service report said. 

Zogg said a few ones northwestern Iowa rivers, including the Big Sioux, may see major flooding as well. 

"What's going to determine whether it actually happens is how rapidly the snow melts as well as any precipitation we get as far as heavy rainfall, thunderstorms," he said. "That'll increase the risk of flooding."

Many rivers away from the borders, near Des Moines, have less than a 50 percent chance flooding, according to NWS data.

"For the larger (central Iowa) rivers, mainly minor-to-moderate flooding," Zogg said. "Not as much of a risk of major flooding that you would see across the eastern part of the state or the northwestern part of the state."

But several waterways on the state's western and eastern borders have a better than 50 percent chance at flooding and some have a better than 50 percent chance of major flooding. 

"The process of melting the snowpack will be essential to the severity of flooding that occurs this spring," the NWS states. "A faster melt combined with heavy spring-time rains could cause high impact flooding, while a slow melt with little additional precipitation would cause flooding to be much less severe."

The Missouri River, along the state's southwest border, is also likely to flood this spring. 

The next scheduled flood outlook is March 7.

Follow the Register on Facebook and Twitter for more news. Tyler Davis can be contacted at 515-284-8378, tjdavis@dmreg.com or on Twitter @TDavisDMR.