Chicago, IL

Weather Forecast Office

Spring Flood Outlook for Northeast Illinois and Northwest Indiana

Outlook Valid
Spring 2023 (March-May)

Last Updated
March 9, 2023

Based on current conditions, the risk of flooding ranges from below average to near average.

The spring flood outlook is updated each February and March. Next scheduled update is spring 2024.

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 2023

Winter 2022-2023 Review

Fall 2022 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.	Below Average to Above Average	Decrease/Increase
Fall/Winter Soil Moisture	Space in soil for additional infiltration.	Below Average to Above Average	Decrease/Increase
Winter Precipitation	Snow cover, the amount of water available for spring melt.	Near Average to Above Average	No effect/Increase
Winter Temperatures	Frost depth, the possibility that infiltration could be blocked by frozen ground.	Above Average	Decrease
Spring Precipitation	Amount of water headed to area rivers.	-	-
Spring Temperatures	Rate of melt for snow cover.	-	-

Valid March 8, 2023.

Current Snow Cover and Snow Water Equivalent

Modeled snow cover across area river basins was generally a few inches or less, which contains 0 inches to 0.25 inches of water equivalent. The deepest snow cover is in central Wisconsin. The majority of the area has no snow cover.

Valid March 8, 2023. Click here for the latest snow cover information.

Current Soil Moisture and Frost Depth

Modeled soil moisture values across the area range from near average to much above average. Values are the lowest in northern Indiana, at the 30th to 70th percentile for this time of year. Values are highest in southern Wisconsin, exceeding the 95th percentile.

Frost depth is near 0 inches across area river basins.

Valid March 8, 2023. Click here for the latest soil moisture information from the Climate Prediction Center.

Current River Conditions

River streamflow across the area ranges from near average to much above average.

River ice spotters, river gauges, and satellite imagery indicate that little-to-no river ice exists on area rivers.

Valid March 8, 2023. 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 couple months) outlook from the Climate Prediction Center indicates below average temperatures slightly favored through at least early to mid March. The outlook indicates above average precipitation is slightly favored by the end of March, especially in northwest Indiana.

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 Advanced Hydrologic Prediction Service (AHPS) page for our area.

Temperature

Temperatures for winter 2022-2023 averaged about 1F to 5F above average in northeast Illinois and northwest Indiana. Although two periods of significant cold occurred, one in late December and another in late January into early February, the rest of winter was near average or above average.

Precipitation

Precipitation for winter 2022-2023 average 0-2 inches above average in northern Illinois and northwest Indiana.

Snowfall

[Valid through March 8]

The first measurable snowfall (>0.1 inches) across northeast Illinois and northwest Indiana (right) occurred later than average, with a few locations seeing minor snowfall by late November, but other locations not seeing snowfall until early to mid December.

The season-to-date snowfall ranged from about 4 inches to about 48 inches across area river basins, with the highest snow totals in southern Wisconsin. Observed snowfall was generally below average in all areas.

River ice conditions in late December and again in late January caused a few minor ice jams but limited-to-no flooding. Very heavy ice cover continued into early February.

Temperature

Temperatures were near average across northeast Illinois and northwest Indiana during fall 2022. Almost all areas experienced temperatures within 1F of average.

Precipitation

Precipitation was near average across northeast Illinois and northwest Indiana during fall 2022. Almost all areas were within 2 inches of the average.