National Weather Service United States Department of Commerce

 

Key Points - issued 3/9/23

  • The risk of spring flooding is above average in southwest Wisconsin
  • The risk of spring flooding is average to above average in south-central Wisconsin
  • The risk of spring flooding is close to average in southeast Wisconsin
  • The risk of spring flooding for the Lower Wisconsin River Valley is above average.
    • Main factors are normal to somewhat below normal water content in the snowpack (this includes the snow forecast March 9-10) and shallower than normal frost depth offset by above average soil moisture and above average streamflow values.
    • River flooding risk for the lower Wisconsin River is above average, mainly due to the unusually deep snowpack in the northern and central portion of the basin. 
  • Additional snow cover could increase this risk. 
  • This flood risk pertains to the underlying risk for the spring season as a whole. The flood risk with any individual rain and snowmelt event could be greater. The greatest potential for flooding will occur if there is heavy rain while the ground is still frozen or if there is a rapid snowmelt along with moderate to heavy rain.
  • A time frame for flood potential is mid to late March if the snowpack remains during that time. Below average temperatures in the next 1-2 weeks may prolong the snowpack, increasing the odds for a rapid snowmelt when temperatures warm up.

What Changed

  • Spring flood risk over the past two weeks increased in the Lower Wisconsin River. There was little change for the remainder of southern Wisconsin, however the risk factors did change. Rivers are running high and soils are somewhat saturated from rain and melting snow at the end of February. As of 3/9 even there is little snow on the ground, but there is still quite a bit of water in the system that plays into outlook.
  • Break up ice jam risk lowered further because there is more open water.

 

Monitor rivers levels here: Current River Levels and Short Term Forecast River Levels

Briefing slides   Recording

 

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