Friday, March 8, 2013

Spring 2013 Flood Outlook

The National Weather Service offices in Davenport and Chicago have both issued a new 2013 Spring Flood & Water Resources Outlook Thursday, March 7th, 2013. The following reasons were given in this new outlook for possible spring flooding:
  • The recent snowfall over the past few weeks has called for a slight increase in the risk of flooding for the spring.
  • A key factor will be the rate of melt from the existing snowpack and how much precipitation we recieve during the melt period of the snowpack.
  • The rate of frost melt beneath the snowpack will also determine the amount of infiltration(process by which water on the ground surface enters the soil) and runoff that will occur.
Image Courtesy of NOHRSC
This image shows us the snow water equivalent of the current snowpack. We have around .5-1.0 inch of water equivalent in the snowpack across the Stateline area currently.

The NWS in Davenport also listed these as the current conditions as of March 7th, 2013:
  • Above normal winter precipitation and snow depth.
  • Near to below normal soil moisture.
  • Deep frost.
  • Near to below normal stream levels.
Also, they listed these following things to keep an eye on for potential changes in in the outlook:
  • Additional precipitation.
  • Frost depth and how it interferes with absorption of snow melt and rainfall.
  • Potential for ice jam flooding.
This was the last of two scheduled spring flood and water resources outlooks for the season.

Also in these outlooks were calculated probabilities for minor, moderate, and major flooding of rivers for 3/11/13 to 6/9/13. Here are some of the outlooks for some of the area rivers:
  • The Pecatonica River near Freeport has a higher than normal probability of exceeding both minor and moderate flooding levels.
  • The Rock River near Como has a higher than normal probability of exceeding all levels of minor, moderate, and major flooding.
  • The Kishwaukee River near Belvidere has a higher than normal probability for minor flooding, but lower than normal probability for moderate flooding.
Outlook from NWS in Davenport
Outlook from NWS in Chicago

Eddie Wildermuth
WTVO Weather Intern

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