Wisconsin Spring Flood Outlook

Conditions as of Feb. 14, 2023

by Sarah Marquardt, Senior Service Hydrologist, National Weather Service

The risk of spring flooding is above normal in the northwest quadrant of Wisconsin, near average in central and northeast Wisconsin, and average to slightly below average in southern Wisconsin. The snowpack’s water content is above average in northwest Wisconsin, a significant factor in the elevated risk of flooding this spring. The snow water content of the snowpack is 4 to 6 inches, which ranks in the 70-100th percentile, meaning amounts are on the higher end of the range of observed historical data. This means that once the snow starts melting, more water than usual will run off into rivers and collect on the frozen ground, elevating the flood risk. Other factors that play into the elevated risk in the northwest quadrant of the state are near-normal river levels and soil moisture. There is room in the rivers to hold some melting snow and spring rain, but it may not be enough, given the snowpack. With the soil moisture close to average, there is the ability of the ground to absorb some of the melting snow, but that also may not be enough to absorb the melting snowpack. Frost depths are shallower than normal for this time of year, meaning it could thaw earlier, allowing for some moisture absorption. This decreases the flood risk somewhat; however, the others outweigh this risk factor.

Elsewhere in the state, mild temperatures over the winter resulted in rain and melting snow at times, limiting snow accumulation. Despite precipitation close to normal (east) or a one to two-inch surplus (west), the snowpack is shallow. The snowpack’s water content is either close to normal (central and northeast WI) or below normal (southern WI). Streamflow and soil moisture is close to normal to slightly above normal due to steady precipitation during the late fall and winter. Frost depths are shallower than usual due to mild temperatures this winter, helping to limit the flood risk somewhat. Putting all these factors together results in near-average flood risk in northeast Wisconsin and near-average to slightly below-average flood risk in southern Wisconsin.

These conditions can change, which can affect the flood risk. Additional snow or rapid snowmelt during a rainy period could increase the risk, and a slow and steady snowmelt during a time with little precipitation will lower the risk. Ice jam-related river flooding is possible when rivers rise and break up the ice. This can be caused by rain running off into rivers or mild temperatures melting the ice. The most susceptible areas are near bridges, river bends, or other areas with restrictions in the river channel where ice chunks can collect, causing the water to back up and result in flooding.

The outlook for the March-April-May season indicates no signal one way or the other for temperature and slightly enhanced odds for above-average precipitation. While it is difficult to predict the timeframe and magnitude of individual storms, now is the time to be prepared for spring flooding. Regardless of the underlying risk, flooding is a threat anytime there is rain while the ground is frozen or if there is rapid snowmelt.

Additional Weather And River Forecast Information

• The 7-day forecast
• Forecast ranges of precipitation – Including a low-end forecast, a high-end forecast, and the most likely amount of precipitation
• NWS river forecasts – At the top of the map is an option to toggle between current river observations and river forecasts. Gauges are color-coded by flood level: no flooding, near flood stage, minor flooding, moderate flooding and major flooding. Click on a gauge to get more information about the river forecast. There is also a “Probability Information” tab with graphics for short and long-term predictions of exceeding river flood stage.

Letter Of Map Change (LOMC) Notifications

A Letter of Map Change (LOMC) is a letter that reflects an official revision and/or amendment to an effective Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM). LOMCs include but aren’t limited to Letters of Map Amendments (LOMAs), Letters of Map Revision Based on Fill (LOMR-Fs), and Letters of Map Revision (LOMRs).

LOMCs can be requested for a variety of reasons, like if a property owner thinks their property has been inadvertently mapped in a Special Flood Hazard Area (SFHA) or if base flood elevations (BFEs) or SFHA extents increase or decrease due to physical changes affecting flooding conditions.

Did you know that the Federal Emergency Management Agency (FEMA) sends determinations for Letter of Map Change (LOMC) electronically rather than mailing paper copies? Please consider subscribing to FEMA’s Flood Map Service Center to receive electronic notifications about new products and determinations. Subscribe here to stay in the loop!

Navigability And Ordinary High Water Mark Determination Training Video

A training video that discusses and demonstrates how to make navigability and ordinary high water mark (OHWM) determinations are available on the DNR Waterways website.

The training was from a 2022 DNR Waterways Program staff training. Since it was primarily for waterways staff (largely chapter 30-related topics), a few of the specific comments may not directly apply to shoreland zoning. However, most of the video applies to making navigability and OHWM determinations for shoreland zoning purposes and understanding the underlying reasons for doing so. The video also explains the Public Trust Doctrine and its role in waterway and shoreland zoning regulations. Thus, most shoreland program partners and others interested in shoreland zoning should find the video helpful.

Aside from using the link above, the video can be found on the DNR website by searching for “waterway jurisdiction determination” or “waterways navigability” and selecting waterways jurisdiction determinations from the list.

New Fact Sheet: Benefits And Costs Of The Community Rating System

Is your community already a participant in the National Flood Insurance Program? Are you ready and willing to do more to protect your community? Communities in the Community Rating System (CRS) get all policyholders in their community a discounted rate on federal flood insurance premiums.

Check out a new Wisconsin DNR fact sheet that outlines the benefits and costs of joining CRS.  

Have questions? Ready to take the next step? Please reach out to us at DNRFloodplain@wisconsin.gov and we will be happy to help you.

Governor’s Proclamation: Flood Insurance Awareness Week, Feb. 6-12, 2023

Most homeowners’ insurance does not cover flood damage. One of the best ways to protect your home and belongings from flood damage is to purchase flood insurance. Flood insurance policies can cover homes, businesses and even renters. Governor Evers proclaimed Feb. 6-12, 2023 to be Flood Insurance Awareness Week in Wisconsin.

As little as one inch of water in a home or business can cause approximately $25,000 in damage. Flood-proofing finances is an important way to stay protected from the potential costs of flooding. Are you ready for spring showers? Visit floodsmart.gov to learn more about federally-backed flood insurance policies.

Update On FEMA’s Elevation Certificate

The FEMA Elevation Certificate (FEMA Form FF-206- FY-22-152) and Dry Floodproofing Certificate for Non-Residential Structures (FEMA Form FF-206-FY-22-153) are currently under review at the Office of Management and Budget (OMB). The form expired on Nov. 30, 2022.

Until the OMB review process is complete, FEMA advises that communities continue to use the existing forms available on FEMA’s website. Following OMB approval, FEMA will issue a memorandum highlighting changes to the forms and update the website for immediate use of the newly approved forms with the new expiration date.

Funding Opportunity: Army Corps Of Engineers Flood Risk Management Request For Proposals

The U.S. Army Corps of Engineers (USACE) Floodplain Management Services (FPMS) Interagency Nonstructural Program is seeking proposals for projects to reduce flood risk. 

All proposals must be interagency and will leverage resources invested by others (monetary or in-kind). At least two governmental or tribal partners beyond USACE must be identified for the effort to be considered interagency. Public-private partnerships are welcome. Proposals may address any or all portions of the flood risk management life cycle (prepare, respond, recover, and mitigate) and may address floods/flood hazards in riverine and coastal areas. Proposals should seek to reduce flood risk through non-structural means.

Examples of nonstructural FPMS products*:

• Flood warning plans
• Floodplain mapping and management
• Structure damage assessments
• Flood emergency preparedness plans
• Dam education and awareness

*Please note that these studies do not result in construction but can help communities better manage their local flood risk.

Studies are typically budgeted at or under $100,000. Proposals should describe work capable of being completed within 12-18 months from initiation, although a 12-month timeline is preferred.

To apply, fill out and submit the proposal template and partner support template to Kira.M.Baltutis@usace.army.mil and David.R.Handwerk@usace.army.mil.

Applications Due: March 15, 2023

Application Documents:

• Proposal Template
• Partner Support Template

View the Call for Proposals here.

Upcoming Floodplain Zoning 3-Part Webinar Series

A new 3-part webinar on floodplain zoning will be offered this March and will introduce participants to basic tools and objectives of floodplain management, ordinance adoption, and administration, specifically in Wisconsin. Please see the link below to access the flyer for more information and registration instructions.

See the webinar flyer for more information.

Other Upcoming Trainings Offered

Upcoming Estimated Letter Of Final Determination (LFD) Dates

About The Wisconsin Floodplain Management Program

The program's goals are to protect life, health and property; to minimize costs for flood control projects; to reduce tax dollars spent for rescue, relief and repair of flood damage; to shorten business interruptions caused by flooding; to prevent future flood blight areas; to discourage victimization of unwary land and home buyers; and to prevent increased flood levels caused by unwise floodplain development.

Contact Us

Floodplain: Brian Cunningham,  Brian.Cunningham@Wisconsin.gov

Shoreland: Kay Lutze, Kay.Lutze@Wisconsin.gov

Dam Safety: Uriah Monday: Uriah.Monday@Wisconsin.gov

Floodplain and Shoreland Management Notes is published by the Wisconsin Department of Natural Resources' Waterways Bureau. The purpose of the newsletter is to inform local zoning officials and others concerned about state and federal floodplain management, flood insurance, shoreland and wetland management, and dam safety issues. Comments or contributions are welcome. Please send comments to DNRFloodplain@Wisconsin.gov.

This newsletter is supported by funding through the FEMA Cooperative Agreement as part of the Community Assistance Program-State Support Services Element of the National Flood Insurance Program. The contents do not necessarily reflect the views and policies of the federal government.