© 2019 Terry Swails

SPRING FLOODING RISK IS HIGH...

March 1, 2019

Welcome to March! While it won't seem like it the next 10 days, the worst of winter is behind us (or at least it should be). The days are getting longer and the sun stronger (at a rapid clip) and it won't be long before we get a taste of spring. In fact, during most years at least one 70 degree day occurs during March in my area. Odds of a 60 degree day are more than 95%!

 

If we get one of those it will help erase the memory of what's happened around the region over the past 50 days which have smashed all sorts of records for snowfall around Iowa, Minnesota, Wisconsin, and NW Illinois.

 

Take a look at Eau Claire, Wisconsin. Over the past 50 days (January 10-February 28) 64.20 inches of snow has fallen. The least during that period was 1.5" in 1964. A typical year would see 16.78".

Rochester, Minnesota is right on Eau Claire's heels with 57.70"

Cresco, Iowa has the most I could find in Iowa with nearly 51 inches.

Here in Cedar Rapids our 50 day total is 42.3. Normal during that stretch is 11.80

In the Quad Cities the number is 39 inches.

For most of the central and upper Midwest this is the snowiest winter since 2007-2008. Many places have seen 4 to 5 feet of the white stuff since it first showed up in October.

The graphic below shows the deepest snow cover currently existing from the northern Iowa border through SE Minnesota into NC Wisconsin. 2 to 3 foot snow depths are measured there.

Another perspective of snow depths.

That snow contains lots of water. According to NOHRSC, the snow pack from HWY 20 in northern Iowa to the Canadian border contains 2-6" of water equivalent. Some places in Wisconsin have up to a 9" water content.

The massive snow cover to the north with its large moisture content raises serious concerns about the potential for spring snow melt flooding on area rivers and streams. This potential is greatly heightened by the saturated soils in the region. Extreme levels of soil moisture in the 99% category exists over much of the central Midwest.

As it stands now, one of the rivers that has the greatest risk of significant flooding is the Mississippi. Over in the Quad Cities the NWS hydrologists are showing a 50% chance of at least a 20.5 foot crest. A 1 in 10 chance of a near record 23.6' crest. Those are extremely high odds of flooding for this point in the game showing the significant risk that's on the table. 

Other variables such as a rapid thaw and heavy precipitation will play a significant role in how the situation plays out. For more on the current spring flood risk for Midwest rivers click on the link below.

Today is a quiet day with minimal weather issues. Temperatures will be cold but better than yesterday with highs in my southern counties where snow cover is minimal pushing 30. Elsewhere 20s will cover it before the Arctic blast arrives Saturday night with wind and sharply colder temperatures by Sunday. Record or near record lows are still on the table for Monday morning. Happy Friday and roll weather...TS

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