Spring Flood Outlook -Updated March 9, 2023

Flood Outlook as of March 9, 2023

River flooding in Wisconsin typically occurs in March and April when there is a rapid snowmelt and/or heavy rain. But, it can happen any time of year when there is heavy rain.

Seasonal Flood Probability Graphics 

Seasonal Flood Probability Table 

Current River Levels and Short Term Forecast River Levels

Flood Risk Factors

Current Conditions (images auto update)

Snow Water Equivalent	Streamflow Compared to Normal	Soil Moisture Percentile

Flood Risk Factors (as of March 9, 2023)

SnowPack

Mild temperatures this winter resulted in rain at times and a lower than normal snowpack. The water content of the snowpack is around 0.25 inches for the Upper Fox River eastward to Sheboygan and close to 0 for the rest of southern Wisconsin. Average is around one half inch to one inch. An additional 0.5 to 1 inch is expected March 8-9 which will bring the snow water content closer to normal for this time of year. If amounts end up being higher than this forecast, the flood risk could be higher.

Snow water content in the Wisconsin River basin is 4-6 inches in the headwaters, 2-4 inches in the central portion of the basin, and around 0.5 inch in the lower portion of the basin. These values in the headwaters are well above average, contributing to the elevated risk.

Streamflow and River Levels

Streamflow values have been close to average to slightly above average at times this winter. Recent melting snow and rain resulted in rivers running above normal. This means there is less room in rivers to collect runoff from melting snow and spring rain.

Soil Moisture

Soil moisture is above average across all of southern Wisconsin due to a wet winter and wet February. The ground is somewhat saturated leaving little room to absorb additional water.

Frost Depth

Frost depth values are a few inches to 0, which is shallower than normal for this time of year.  This helps to decrease the flood risk somewhat because the ground can absorb melting snow and spring rain. However, there will still be a moderate amount of runoff because the vegetation is still dormant.

Rivers and Ice

Mild temperatures over the past two weeks have allowed some melting of ice in rivers, further lowering the ice jam risk. There are many areas with open water, although some rivers and lakes do have some ice cover, so flooding due to ice jams is still a threat. Ice jams occur when rivers rise due to melting snow and rain and ice starts to break up and move downstream in the river. Sometimes it jams up resulting in some flooding. The most susceptible areas for ice jam related flooding are at bridges, river bends or other areas with restrictions in the river channel where ice chunks can collect and cause flooding.

Looking Ahead (images auto update)

7 Day Precipitation Forecast

Extended outlooks from the Climate Prediction Center:

How To Prepare Safety

Preparedness/Early Actions:

• Get a NOAA Weather Radio to be alerted to flash flood warnings and river flood warnings
• Monitor weather forecasts for heavy rain potential
• Have a communications plan for your family and a place to meet in higher ground.
• Monitor river levels and forecasted river levels online: (National Site, USGS, MKX)
• Know a safe way to exit your home and neighborhood and avoid any roads susceptible to flooding
• Prepare your home:
  • Consider flood insurance, especially if you are in a flood prone area - (may require 30 day notice)
  • Make sure your sump pump is working and consider a backup.
  • Have a professional install check-values to prevent floodwaters from backing up into the drains of your home
  • Keep important documents in a waterproof, elevated container, not in the basement.
  • Remove snow from roof, downspout area, and away from base of home
  • Finish any outdoor projects that may be affected by heavy rain or flood waters
• Prepare (Flood Ready, Flood Safety) 

How To Stay Safe During a Flood:

• Heed evacuation orders and evacuate your home if it is at risk
• Turn Around, Don't Drown - never drive through flooded roads
  • You do not know how deep the water is or if the road has been washed out
  • You may damage your vehicle
  • You put yourself and first responders at risk

Briefing Slides

Feb 9, 2023  Webinar Recording and Slides

Feb. 24, 2023  Slides

Mar. 9, 2023 Webinar Recording and Slides

Information about the spring flood outlook across the entire Upper Mississippi River basin here.

If you have any questions or comments about this spring flood outlook please contact:

Sarah Marquardt

Senior Service Hydrologist

National Weather Service Milwaukee

sarah.marquardt@noaa.gov