More extreme rainfall expected in a warming climate

This week, parts of Missouri saw it's most significant rainfall and flooding on record. More than a foot of rain fell in southeastern Missouri, inundating farm fields and entire towns.

But this isn't a headline that's new. We have seen more extreme rainfall events in the Upper Midwest in the past decade than in a lifetime! And in order to understand the frequency, one just has to look at the top five records on a lot of our rivers. The significant crests that occurred since 1993 are in bold.

  • Mississippi River at Rock Island, Illinois:
    (1) 22.63 ft on 07/09/1993
    (2) 22.48 ft on 04/28/1965
    (3) 22.33 ft on 04/25/2001
    (4) 22.00 ft on 03/10/1868
    (5) 21.49 ft on 06/16/2008
  • Mississippi River at St. Louis, Missouri:
    (1) 49.58 ft on 08/01/1993
    (2) 43.23 ft on 04/28/1973
    (3) 42.52 ft on 01/01/2016
    (4) 42.00 ft on 04/01/1785
    (5) 41.89 ft on 05/22/1995
  • Cedar River at Cedar Rapids, Iowa:
    (1) 31.12 ft on 06/13/2008
    (2) 21.95 ft on 09/27/2016
    (3) 20.00 ft on 03/18/1929
    (4) 20.00 ft on 06/01/1851
    (5) 19.66 ft on 03/31/1961
  • Illinois River at Peoria, Illinois:
    (1) 29.35 ft on 04/23/2013
    (2) 28.80 ft on 05/23/1943
    (3) 28.70 ft on 03/23/1979
    (4) 28.40 ft on 03/07/1985
    (5) 27.94 ft on 03/14/2009
  • Missouri River at Gasconade, Missouri:
    (1) 39.60 ft on 07/31/1993
    (2) 39.00 ft on 05/04/2017 preliminary
    (3) 38.60 ft on 10/06/1986
    (4) 37.90 ft on 12/30/2015
    (5) 37.60 ft on 05/19/1995

So, why are we getting more extreme rain events? And can we link this to climate change? According to Climate Central, for every 1°F of temperature increase, the atmosphere can effectively hold 4% more water vapor. Quite simply, the warmer the atmosphere (as it was in much of early Spring 2017), the more rainfall.

Click here for local river levels

Once the flood waters recede and insurance claims are completed, this week's flooding in Missouri will likely be in the hundreds of millions of dollars. And buckle up because the next big flood event/disaster like this is could come in the next few months. According to NOAA's Weather Prediction Center, a zone of heavy rainfall from San Antonio, east into Louisiana and Mississippi has the highest threat for significant flooding in the next month.

And even if the next extreme flood happens there, every event has an impact on everyone else because it translates into higher insurance premiums and an increase need for relief efforts.

-Meteorologist Eric Sorensen