September 20, 2024
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Outlook cites spring flood risk along Mississippi River, less along Rock River

By Troy E. Taylor
Ice was prevalent on the Rock River but the main stream was still flowing in this photo taken Dec. 28, 2022. The National Weather Service said flood risk for interior streams such as the Rock River are less than 50%, according to its long-range outlook.

Ice was prevalent on the Rock River but the main stream was still flowing in this photo taken Dec. 28, 2022. The National Weather Service said flood risk for interior streams such as the Rock River are less than 50%, according to its long-range outlook. (Troy Taylor)

DAVENPORT, Iowa – The spring flood risk along the Mississippi River is slightly above normal, and it is below normal for tributary streams such as the Rock River, the National Weather Service said in its March to May outlook.

“A lot of the flood risk here is going to depend on the rate of snow melt, any additional snowfall that we get during the course of rest of the winter and spring, and if there are any heavy spring rains and their frequency,” said Matthew Wilson, senior service hydrologist at the Quad Cities station.

Snow pack in the upper reaches of the Mississippi River basin were above average this winter.

A bald eagle flies above the Mississippi River below Lock & Dam 13 between Thomson and Fulton in January 2023. Numerous bald eagles can be seen along that area as the birds forage for fish in the open water below the dam.

A bald eagle flies above the Mississippi River below Lock & Dam 13 between Thomson and Fulton in January. The National Weather Service said the spring flood risk is above normal for locations such as this because of heavier snow pack in the upper basin of the watershed.

If snow melts rapidly over frozen ground in Minnesota and Wisconsin, it would increase the flood threat in the vicinity of the Dubuque and then at the Fulton Lock and Dam and all points south.

However, if the snow melt takes place after the frost retreats, then the ground will be able to store more water and lessen the flood risk, according to the outlook.

The service is forecasting spring precipitation that is above normal. Yet, as river levels in the upper Mississippi River watershed are running near normal, this provides more capacity to handle heavy spring rains.

A map from the National Oceanic and Atmospheric Administration and the United States Geological Survey shows long-range flood risk on waterways in Iowa and northwest Illinois. Points in green are slight risk, orange are minor risk and red are moderate risk.

A map from the National Oceanic and Atmospheric Administration and the United States Geological Survey shows long-range flood risk on waterways in Iowa and northwest Illinois. Points in green are slight risk, orange are minor risk and red are moderate risk. (National Weather )

The service said there is no clear signal on temperatures – and their effect – because of the transition from La Nina to El Nino conditions in the Northern Hemisphere.

Cold temperatures in early February have increased the prevalence of ice on the Rock River, the service said. The breakup of remaining ice jams on the Rock River is a neutral threat, however, and should take place in the next week.

In Illinois, the Pecatonica, Rock, Green and LaMoine rivers all have a lower flood risk because winter snow and rain has been at average levels.

The weather service cautions that the long-range forecast does not eliminate the chance of floods, it only indicates that the chance of it happening is less than half.

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Troy Taylor

Troy E. Taylor

Was named editor for Saukvalley.com and the Gazette and Telegraph in 2021. An Illinois native, he has been a reporter or editor in daily newspapers since 1989.