National Weather Service: Above-Average Risk of Spring Flooding on Fox River

National Weather Service: Above-Average Risk of Spring Flooding on Fox River

The National Weather Service Chicago is saying snow melt, soil moisture and present river levels are adding up to an above-average risk of flooding along the Fox River this spring.

Fox River flooding in Algonquin in September 2017.

According to the NWS Spring Flood Outlook, the risk of flooding ranges from “near average” to “much above average.”

“The greatest risk of flooding is in the Fox, Kishwaukee, Pecatonica, and Rock River basins,” the NWS Chicago said. “Additional rainfall or snowfall may change the risk of flooding later this spring.”

As far as the spring weather outlook, the NWS-C is almost perfectly non-committal.

“The long term outlook from the Climate Prediction Center indicates near equal chances of below average, near average, or above average temperatures and precipitation,” the Weather Service said.

Current Snow Cover and Snow Water Equivalent

Current Modeled Snow DepthCurrent snow water equivalent

Valid Feb.21, 2019. Click here for the latest midwest snow analysis information.

Modeled snow cover (above, left) across the area ranges from near 0 inches to near 8 inches, which contains 0 inches to 1 inch of water equivalent (above, right).

A few isolated areas may have snow cover up to 10 inches in depth and 2 inches of water equivalent.

The deepest snow cover was in far northern and northwestern Illinois and the highest water equivalent was in a few isolated areas near Rockford. The majority of the area had snow water equivalent of less than 1 inch.

Current Soil Moisture and Frost Depth

Valid Feb. 20, 2019. Click here for the latest soil moisture information from the Climate Prediction Center.

Modeled soil moisture values across the area range from slightly above average to much above average, with the highest values in far northern and northwestern Illinois.

Frost depth was generally 8 to 10 inches across the area, with a few areas possibly as low as 4 inches.

Current River Conditions

USGS streamflow conditions for the United States

River levels across the area (above) ranged from near average to above average. The highest river levels were in the Rock River basin in northern Illinois.

River ice spotters report a few areas of heavy ice cover remaining along the Des Plaines River, Fox River, and Rock River. The general trend is toward diminishing ice cover. River ice may cause ice jams this spring, but the risk is low as of this outlook.

Valid Feb. 19, 2019. Click here for the latest streamflow conditions from the USGS.

Detailed Flood Outlook

Click here for the detailed Spring Flood Outlook which includes tables with probabilities of flooding along area rivers. Relative flood risk can also be viewed on the Advanced Hydrologic Prediction Service (AHPS) page for our area.

SOURCE: National Weather Service Chicago