Flood Risk Rises With Incoming Warmth, Rain

By Alex Sosnowski, Expert Senior Meteorologist

February 20,2014; 2:00PM,EST

 

 

The combination of rain and melting snow will lead to flooding problems on streets and highways as well as along some streams in part of the Midwest and the Northeast Thursday into Friday.
The most common problem will stem from storm drains and catch basins that are clogged with snow. Water will also be trapped on frozen ground in yards and fields.
Rising temperatures, moist air and rain with localized downpours are forecast.
While not all of the snow will melt throughout the Midwest and Northeast, in areas where it does vanish, this combined with the rainfall can cause small stream flooding to occur.

This is most likely in the northern Ohio Valley states to New York state, central and southern New England, much of Pennsylvania, northern New Jersey, northern Maryland and the area along the Virginia/West Virginia border.
While a general 0.50-1.00 inch of rain is forecast, some locations can receive between 1 and 2 inches of rain.
The existing snow cover contains between 1 and 4 inches of rain with greater amounts near the Canada border. The snow will absorb much of the rain over a large part of the region, but there will be some exceptions.
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Downpours will be focused enough from thunderstorms to cause small scale flooding issues.

Similarly not enough of a thaw and rainfall are expected by National Weather Service hydrologists to lead to widespread major river flooding.
According to National Weather Service Hydro-Meteorologist Ted Rodgers, "We do not anticipate enough rain and natural melting for major flooding at this time, but sporadic minor flooding incidents are possible."
Rodgers stated the same level of concerns follow through with ice jams.
"The snow cover is so extensive and the ice is so thick on area streams and lakes that it will work against very high temperatures and will not melt all at once in this case," Rodgers said.
Other problems the warmup and rain will bring range from potholes to water main breaks, fog, falling ice from buildings and bridges, leaky roofs and roof collapses.
The warmup will reduce the snow cover and allow some folks who have been shut in to get some fresh air. Many schools and parents will be able to resume daily activities for a time.