Thaw to Raise Flooding Concerns in Midwest, East

By Alex Sosnowski, AccuWeather.com Senior Meteorologist

March 6,2015; 10:45PM,EST

 

 

The combination of warmer weather moving in with melting snow will bring the potential for flooding on small streams and rivers in parts of the Midwest and East through the middle of March.
While the overall flooding risk is low due to a lack of heavy rain forecast, the risk is greatest in parts of the Midwest in the short term.
Temperatures are forecast to rise well into the 50s and 60s in the Ohio Valley this coming week.
Deep snow cover is still present in many areas. The snow cover contains up to several inches of water.
Even though the rain during the middle of the week eroded much of the old snow cover from Kentucky to West Virginia, western Maryland and southwestern Pennsylvania, new snow fell on much of the region from the storm on Thursday. Between 6 and 18 inches of snow fell from the most recent storm in part of this area.

A number of streams in the Midwest and Northeast are still covered by a thick layer of ice, have ice flows or are running high following recent rainfall.

While the high water scoured out a significant amount of ice on streams late this week, some ice remains in the central Appalachians. Runoff created by the melting snow cover and saturated ground beneath could bring another round of flooding from the Ohio Valley to part of the central Appalachians this coming week.
Rescue crews work in flood waters on Thursday, March 5, 2015, around Coal Run, Kentucky. (Photo/Coal Run, Ky., Mayor Andrew H. Scott)
From the upper Great Lakes region to northern Pennsylvania, upstate New York and New England, temperatures are not likely to get high enough long enough to bring a high risk of ice jam flooding this coming week. Daytime highs above freezing and nights near or below freezing will slow the runoff.
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The existing snow cover in the Upper Midwest and Northeast also contains layers of ice, which tends to melt more slowly than recent fluffy snow.
In the northern areas, the weather pattern next week is favorable for a more gradual thaw. A significant amount of the snow and ice cover are likely to remain.
The milder weather forecast to move in will raise the temperature of the existing snow and ice cover, perhaps making it more prone to a rapid thaw later. As a result, flooding could still occur in the weeks ahead.
AccuWeather.com meteorologists will be watching the progress of a southern storm next week. While the storm is currently forecast to slide south of areas with the greatest snow cover, a shift in the storm track could bring rain farther north.
A second storm with rain could take a path much farther to the north next weekend, continuing the concern for flooding through most of March.
AccuWeather.com will provide updates on the storm and potential flooding.