Ice Jams on Area Rivers and Streams

Ice Jams on Area Rivers & Streams

 The bitter cold temperatures over the last few days have increased ice production on area rivers and streams. Ice jams were reported on portions of Sangamon and Mackinaw Rivers.

Water levels can fluctuate rapidly in the vicinity of ice jams. Ice jams also tend to cause localized flood problems with some areas experiencing flooding, while other locations on the river may not encounter any flood problems. A large, newly forming ice jam will cause water rises in locations upstream of the jam. Generally, this location will be in a sharp bend in the river or at a junction where a large tributary enters the main channel. Other favored locations are bridges with poor flow capacity, islands, and at the headwaters of lakes.

Additional ice accumulation on these and other area rivers are expected with the continued cold temperatures over the next several days. Residents living in low lying areas along rivers that are prone to ice jams should continue to closely monitor water levels and be prepared to move quickly if ice jam flooding threatens.

The images below provide a comparison of the current ice jams to normal flows along these rivers.

Sangamon River
Chandlerville - Upstream (1/5/10)

Sangamon River
Chandlerville - Upstream

Sangamon River
Chandlerville - Downstream (1/5/10)

Sangamon River
Chandlerville - Downstream

Mackinaw River
Green Valley - Upstream (1/5/10)

Mackinaw River
Green Valley - Upstream

Mackinaw River
Green Valley - Downstream (1/5/10)

Mackinaw River
Green Valley - Downstream



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