Flooding outlook low for Cedar River in CC

March rain or snow the wildcard as current snow pack a non-factor

Staff Report

Any flooding of the Cedar River in Charles City this spring will not be caused by the existing snow on the ground in its watershed. It will take March rains or heavy snows to stir concern.

The spring flooding outlook released Thursday by the National Weather Service warns of flood potential near to slightly above normal in a region that includes southern Minnesota, southwest-to-central Wisconsin and north eastern Iowa. The Mississippi River and some Wisconsin tributaries already experienced flooding already and continue to have an elevated flood risk.

Locally, the Cedar River forecast bucks that trend.

Charles City has lower-than-normal chances of seeing even minor flooding. The probability of exceeding the 12-foot minor flood stage is 11 percent. Normally it’s 21 percent. The chance of exceeding the 15-foot moderate and 18-foot major stages is less than 5 percent. Normally, there is a 10 percent chance at moderate and 6 percent chance of major flooding.

Many rivers in the region are experiencing above-normal levels for this time of year in part because “soil moisture across the region is high due to heavy rains last  summer and early fall,” the outlook says.

An unusually warm February has melted much of the snow pack across the region.

“The only snow still on the ground at this time is located from southeast Minnesota northeastward into north-central Wisconsin and in central and southwest Wisconsin,” the outlook says. “This snow contains up to three-quarters of an inch of water.”

The outlook forecasts that March has an enhanced chance of continued warmer-than-normal temperatures and above normal precipitation, which would be the main driver of flooding concerns going into this spring.

Continued melting of the snowpack by unusually warm temperature will make many rivers rise this weekend. However, from March 5 through June 3, the Cedar River in Charles City will most likely stay between 6.4 feet and 7.1 feet. There is a 50 percent chance that it will reach 8.2 feet and a 5 percent chance it will climb to 14.8 feet.

The outlook contains information collected from a number of sources, including the United States Geological Survey, U.S. Army Corps of Engineers, Midwest Regional Climate Center, High Plains Regional Climate Center, and U.S. Drought Monitor and the National Operational Remote Sensing Center.

— 20170303 —