2021 Spring Flooding Outlook

What's Happening Now

The overall risk for Spring snowmelt flooding remains near normal.  Stream levels are currently running near normal except for areas where ice may be causing localized elevated water levels.

Snow cover is around normal for this time of year and even a little below in some areas.  However, there are a few areas that received some heavier snow this winter across northeast Iowa and southwest Wisconsin where as much as 12 to 18 inches of snow is on the ground with a water content of 2 to 4.5 inches.  Above normal temperatures are forecast the next few weeks and this will likely melt a good portion of the snowpack across the area.  These areas with deeper snowpack will have to be watched more closely as the thaw continues this Spring.  Potential river basins impacted include portions of the Turkey River, Kickapoo River, and the Platte River and Grant River.

What Can We Expect This Spring and Why

The overall risk for flooding is near normal this Spring for the mainstem of the Mississippi River and Tributaries.
Factors for a near-normal flooding risk this spring:
  1. Overall drier conditions during the late Summer and Autumn of 2020 continued into this winter.
  2. Limited snowpack this winter. Areas of deeper snowpack over northeast Iowa and southwest Wisconsin.
  3. Lower soil moisture, not saturated like we saw last year.  Higher soil moisture in some areas over northeast Iowa and southwest  Wisconsin.
  4. Frost depth is generally shallow this year ranging from 5 to 16 inches. Less frost in the ground suggests that once snow starts melting, there will be more infiltration into the soil and less runoff.
  5. Cold, below normal temperatures through mid February, increased ice cover and thickness on area rivers possibly increasing the chances for a few ice jams depending on the amount and rate of runoff and future precipitation . Ideal melting conditions (warming above freezing during the day and then refreezing at night) can slow the runoff and could reduce the potential for ice jams.

Preparedness Information

  • A near-normal flood risk means the chances for spring snowmelt flooding are near normal based on historical data and current conditions.  Future temperature and precipitation trends may increase or decrease the flooding threat, monitor information from the National Weather Service.
  • Live in a flood prone area? Consider flood insurance (may require 30 day notice).
  • Prepare your home by making sure your sump pump is working and consider a backup.
The next scheduled Spring Flood Outlook update will be issued on Thursday March 11th.