Midwest, Northeast Face Local Flooding as Warmup Spurs Snowmelt

By Alex Sosnowski, AccuWeather.com Senior Meteorologist

March 9,2015; 8:51PM,EDT

 

 

Flooding problems will continue in part of the Ohio Valley and could expand into the Northeastern states as the week progresses.
More Flooding Likely in Ohio Basin
Melting snow and runoff spurred on by warmer weather will have streams running high in the Ohio River Basin.
To complicate matters, rounds of rain are forecast across portions of the Tennessee and Ohio valleys to part of the central Appalachians through this coming weekend.
"On Tuesday, the rain starting the new week around Texas will spread to the Tennessee and Ohio valleys and mid-Atlantic through Tuesday," AccuWeather.com Senior Meteorologist Kristina Pydynowski said.
Minor flooding will continue to work downstream along the Ohio River through the week. In some areas below Cincinnati, it may not be until the weekend before water levels slip below flood stage. The flooding will generally be limited to low-lying parkland, marinas and roads along the river.

Moderate flooding will occur along some of the rivers that feed into the Ohio River this week, particularly in Kentucky.
The additional rain into this weekend could lead to additional surges of high water along the Ohio River and its tributaries in the coming days in parts of Kentucky, Ohio, Indiana, West Virginia and southern Pennsylvania.
RELATED:
Current Flood Advisories
Forecast Temperature Maps
Springlike Warmth to Spread Across Midwest, Northeast This Week
Flooding Risk Could Expand to Upper Midwest, Northeast
As the snow begins to melt over the countryside farther to the north, increasing runoff into area creeks and rivers could lead to ice-jam flooding in parts of the Upper Midwest and Northeast. Many streams in the Northeast are still locked in ice. In some areas, 2 feet or more of snow and ice remain on the ground. This snow and ice cover contains several inches of water.

The amount of runoff will be determined by how quickly the temperature of the snowcover climbs to the 32-degree Fahrenheit mark. At the start of the week, the temperature of much of the snowcover from northern Pennsylvania to Maine was in the middle 20s. Several days with air temperatures averaging near or above the freezing mark will cause the snow and ice cover to warm up and begin to melt.
Thus far in much of New England and the northern mid-Atlantic, melting has been restricted to urban areas where temperatures have averaged higher.
From the upper Great Lakes region to upstate New York and New England, temperatures are not likely to climb high enough for long enough to bring a high risk of ice-jam flooding this coming week. During much of the week, daytime highs above freezing and nights near or below freezing are forecast and should slow the runoff.
The existing snowcover in the Upper Midwest and Northeast also contains layers of ice, which tend to melt slowly in the absence of heavy rain, prolonged warmth and very moist air.
However, predicting how each and every stream will react to the warmth is challenging and there are likely to be some flooding problems this week and next week, even in the Northeast.

A second dose of rain will move up from the Gulf of Mexico this weekend. Early indications are that storm will bring a wintry mix to New England, but could bring drenching rain to parts of the Ohio Valley and mid-Atlantic.
As a result, people with homes and business along streams and rivers in the Midwest and Northeast should remain vigilant. This includes communities not protected by levees along the Susquehanna, Potomac and Delaware rivers.
As the ice begins to break up, it could damage structures along the creeks and rivers in the absence of significant flooding.
AccuWeather.com will provide updates on the potential flooding risk.