Higher risk of major spring flood
By Shelia Tomkins
A much higher chance of major spring flooding along the Mississippi River and most of its tributaries across northeast Iowa, southwest Wisconsin and southeast Minnesota was predicted by the National Weather Service in LaCrosse, Wis., on Thursday, March 7.
The report was the second of the season issued by the NWS, and showed an even higher risk than predicted in its first report, due to additional heavy snow upstream in Wisconsin and Minnesota.
At Guttenberg, the NWS predicts a greater than 95% chance of major flooding. The average chance of a major flood here is 11%.
Major flood stage at Guttenberg is 21 feet or higher; the record high was in 1965 with a crest of 23.65 feet. As of March 9, river stage here was 7.38 feet.
Contributing factors for the high flood potential include expansive snow cover across the region with 2-4 inches of water in the snow; thick river ice; persistant higher-than-normal flows this winter, and saturated soils due to a very wet fall.
Many variables will affect the river's rise, including the speed of the snow melt and additional precipitation this spring. The NWS report notes that gradual snow melt and/or light precipitation could lower the risk; on the other hand, significant rainfall and/or a rapid snow melt would compound flooding potential.