Heavy Rain and Snow Melt Likely to Cause Areas of Flooding

Considerable snow melt has occurred since Tuesday across central Illinois. This melting will accelerate today.  However, the frost depth is ranging from 10 to 15 inches in much of the area, so the melting snow will run off instead of soaking into the ground.  Observations from area weather observers, and analysis from the National Operational Hydrologic Remote Sensing Center near Minneapolis, indicates that this snow pack contains 1 to 2 inches of liquid within it. 

A storm system will be moving through the Midwest today, bringing rain to central Illinois. Current indications are that an inch of rain is likely from around Rushville to Bloomington northward, with 3/4 to 1 inch closer to the I-72 corridor.  This also will be running off.

With all of the liquid running off instead of soaking into the soil, areas of flooding will be common over the next few days. This is most likely in normally poor drainage areas, plus in city or town locations where storm drains are blocked by snow banks, which will take a longer time to melt.  With this threat in mind, a Flood Watch remains in effect through 6 PM today for much of central Illinois.

Along area rivers, the ice cover will be breaking up due to the warm weather, and the runoff will cause it to float downstream.  This will lead to the potential for ice jams near bridge piers and other areas where the river channel is constricted.  Ice jams can result in erratic river levels and significant flooding near the site of the jam.  Even if no ice jams occur, the rain and the snow melt will result in significant rises the next few days, and minor flooding may result on rivers. Portions of the Spoon, Illinois, Embarras, Little Wabash, and Wabash Rivers currently appear are most at risk for river flooding to develop. If you have interests along area rivers, keep an eye on river stage forecasts and be prepared to take action if necessary.

 

Latest snow depth map

48-hour precipitation forecast

Observed morning snow depth
(click to enlarge)

Forecast rainfall next 48 hours
(click to enlarge)

 

 

 



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