Chicago, IL

Weather Forecast Office

Spring Flood Outlook for Northeastern Illinois and Northwestern Indiana

Outlook Valid
Spring 2025 (March-May)

Last Updated
February 13, 2025

Based on current conditions, the risk of flooding during spring 2025 ranges from below average to near average across river basins in northeastern Illinois and northwestern Indiana.

The spring flood outlook is updated each February and March. Next scheduled update is February 27, 2025.

Risk Factors for Spring Flooding

To determine the relative risk of spring flooding, numerous factors are considered including snow cover, soil moisture, and current river conditions. A significant snow cover with high water content can increase the chances of flooding once warmer weather melts the snow. Elevated soil moisture conditions reduce the amount of rainfall that is soaked up by the ground and increase the amount of water that then runs off into area streams. Above average river levels reduce the river rise required to reach flood stage, while below average river levels would require an increased amount of river rise to reach flood stage.

Spring Flood Outlook

Winter 2024-2025 Review

Fall 2024 Review

Spring Flood Risk Factors

Here is a general overview of spring flood risk factors across northeast Illinois and northwest Indiana river basins.

Risk Factor	Has effect on...	Current Condition	Effect on Flood Risk
Fall/Winter River Levels	Space in river for additional streamflow.	Much Below Average to Near Average	Decrease/No effect
Fall/Winter Soil Moisture	Space in soil for additional infiltration.	Below Average to Near Average	Decrease/No effect
Winter Precipitation	Snow cover, the amount of water available for spring melt.	Below Average to Near Average	Mixed
Winter Temperatures	Frost depth, the possibility that infiltration could be blocked by frozen ground.	Above average trending to below average	No effect
Spring Precipitation	Amount of water headed to area rivers.	-	-
Spring Temperatures	Rate of melt for snow cover.	-	-

Valid February 13, 2025.

Current Snow Cover and Snow Water Equivalent

Modeled snow cover across area river basins ranges from 1 to 3 inches across area river basins, which contains up to 0.25 inches of liquid water equivalent.

Valid February 13, 2025. Click here for the latest snow cover information.

Current Soil Moisture and Frost Depth

Modeled soil moisture values across the area are generally below average.

Frost depth ranges from near 7 inches in northern Illinois to over 20 inches in south central Wisconsin. Frost depth is generally above average for this time of year across area river basins.

Valid February 13, 2025. Click here for the latest soil moisture information from the Climate Prediction Center.

Current River Conditions

River streamflow across the area range from below average to near average.

River ice spotters, river gauges, and satellite imagery indicate that only limited areas of heavy ice cover remain in place on area rivers. The risk of ice jam related flooding is low at this time, but may increase in the coming weeks due to the possibility of very cold weather.

Valid February 13, 2025. Graphics update daily. Click here for the latest streamflow conditions from the USGS. Click here for the latest river ice spotter reports.

Spring Weather Outlook

The long term (next several weeks) outlook from the Climate Prediction Center indicates below average temperatures are favored but no strong signal for precipitation.

Although snow cover, soil moisture, and recent river levels can provide some indication of the relative risk of spring flooding, any weather system that produces heavy rainfall could cause flooding. Spring flood outlooks are not able to assess the risk of flooding due to heavy rainfall more than a week or so in advance.

Detailed Flood Outlook

Relative flood risk for river forecast locations can be viewed on the National Water Prediction Service (NWPS) page for our area.

Temperature

Temperatures for winter 2024-2025 averaged about 1F below to 2F above average across northeastern Illinois and northwestern Indiana. Although temperatures were generally near average, multiple periods of very cold temperatures contributed to deeply frozen soils across the area by early February.

Valid as of February 13, 2025.

Precipitation

Precipitation for winter 2024-2025 averaged 0-3 inches below average across northeastern Illinois and northwestern Indiana.

Valid as of February 13, 2025.

Snowfall

The first measurable snowfall (>0.1 inches) in northeastern Illinois and northwestern Indiana (right) occurred mid-to-late November in most areas.

The season-to-date snowfall ranges from about 4 inches to about 18 inches across area river basins, with the highest snow totals in northern Indiana and southern Wisconsin. Observed snowfall was generally below average in all areas.

River ice became widespread on area rivers by the middle of January with a few minor ice jams reported. Most ice jams did not produce any flooding. River ice cover decreased significantly by early February.

Valid as of February 13, 2025.

Temperature

Temperatures were generally above average across northeastern Illinois and northwestern Indiana during fall 2024. Temperatures were 3-6F above average according to the Midwestern Regional Climate Center.

Precipitation

Precipitation was generally below average across northeastern Illinois and northwestern Indiana during fall 2024. Precipitation was 1-6 inches below average according to the Midwestern Regional Climate Center.