Ice Jam Flooding Possible

The recent rain and rapid fluctuation of temperatures recently has caused some concern for possible ice jam flooding along some of the local rivers.

A Flood Advisory remains in effect for the Rock River at Byron and for the Pecatonica River near Shirland through Friday evening. 


Current stage of the Rock River at Byron was 10.2 feet and ice affected.  Action stage is 10.5 feet and flood stage is 13 feet.  Current forecast for the Rock River is to rise near 'action stage', or near 10.5 feet by Thursday morning.


Current stage of the Pecatonica River at Shirland is 9.9 feet and was ice affected.  Action stage is 11 feet and flood stage is 12 feet.  Current forecast for the Pecatonica River is to rise near 'action stage', or near 11 feet by Friday morning.


Ice jam cause river levels to quickly fluctuate with very little warning.  The ice jams typically form along bends within the river or where ice can become stuck as it flows downstream.  When an ice jam occurs, flooding occurs upstream of the jam as the water becomes 'backed up'.  Once the ice jam breaks free flooding may then occur downstream due to the rapid rush of water. 


Residents living in low lying, flood prone areas need to remain alert for the potential of flooding due to ice jams.