Homeland Security Threat Level: YELLOW (ELEVATED)

Significant National Weather

South:
Showers and thunderstorms will move eastward from the Middle Mississippi Valley into the Carolinas and Florida. Rain across Florida may be accompanied by locally severe thunderstorms; some parts of central Florida may see over four inches of rain by Friday. Strong to severe thunderstorms are possible near the Gulf Coast, from southern Mississippi to the Florida Panhandle.

Midwest:
Widespread showers and thunderstorms are expected for much of the South Central U.S., from the Middle Mississippi Valley into the Southeast today and continuing into the Ohio Valley and Central Appalachians on Friday. A few thunderstorms over southern Illinois, southern Indiana and western Kentucky could become strong to severe. Light snow will develop over parts of the Central Plains to the Northern Plains and tapering off to parts of eastern Nebraska by Friday evening. Scattered rain will fall from northern Minnesota to western Missouri. Rain and embedded thunderstorms are forecast from southern Wisconsin to Kentucky.

West:
Moderate to heavy rain will develop along the West Coast from central California to Washington. Light snow is expected over the higher elevations, extending into parts of the Northern Intermountain region. Over a foot of snow is possible in the Cascades by Friday evening. Light snow will also develop over parts of the Southern and Central Rockies.

Northeast: 
Light showers will develop across West Virginia and western Virginia during the afternoon. Rain is expected across the region on Friday and will continue through the weekend. The combination of rain, melting snow with high water content, and warmer temperatures will increase flooding from West Virginia to New England, especially around creeks, streams and rivers near the Appalachians. (NOAA’s National Weather Service, Hydro Meteorological Prediction Center, and various media sources) 

Flooding Increasing in NCRFC Forecast Area (as of March 10, 2010)

Rain will continue across the North Central River Forecast Center (NCRFC) forecast region for the next few days. The heaviest daily rain totals are expected by Friday morning with amounts around a half to one inch across parts of Minnesota, Iowa, Illinois, Wisconsin, northern Indiana, and lower Michigan.

Widespread flooding continues to increase as rain and warmer temperatures continue to impact the region. At this time, the most significant flooding is focused in Iowa although the area of concern will likely increase as several days of rainfall is expected to help melt any remaining snowpack and contribute runoff to the system.

Moderate to major flooding is observed or forecast on rivers and streams in Iowa, southern Wisconsin, and Illinois. Moderate flooding is forecast for parts of the Mississippi River along the state borders of Illinois and Missouri. Minor flooding is occurring or forecast in parts of Iowa, Missouri, Illinois, and Wisconsin.  These forecasts may increase as the forecast rainfall amounts and placement become clearer in the next couple of days.

By the end of the week, it is likely that conditions will be in place to start causing significant rises in streams further north in Minnesota, Wisconsin, and lower Michigan. In addition, ice jam potential still remains on many of our rivers, especially in northern Illinois, Iowa, and the rest of our northern-most locations.  Ice jams have been reported over the past couple of days in southern Iowa. 

The NCRFC is extending operational hours, with a hydrologist coming on duty at 4:00 a.m. today.

For additional and more in-depth information concerning river forecasts, precipitation, and all hydrometeorological information in the NCRFC area of responsibility, please refer to the NCRFC web page at: http://www.weather.gov/ncrfc. (NOAA’s NWS NCRFC) 

Ice Jams Complicate Spring Flooding Across the United States

As temperatures rise across the U.S., snowmelt and heavy spring rains increase the threat of seasonal flooding. However, warm temperatures over the past weekend brought residents in southeast Iowa another threat, ice jams. Ice jams are expected to affect many rivers across the Plains, portions of the Mississippi Valley, Midwest and New England this spring. 

On March 10, 2010 residents and local officials in Nebraska began coping with the threat of two ice jams colliding and flooding homes along the Loop River in Nebraska. 
An ice jam is an accumulation of ice in a channel that restricts the flow of water. This flow restriction can lead to rapid and substantial increases in river levels upstream of the jam and equally substantial decreases in river levels downstream. Ice jams can cause severe local flooding and disrupt navigation, municipal water supplies, and hydropower operations. When they break up and flow downstream, they may erode river beds and banks, destroy wildlife habitat and damage structures such as bridges and dams. Ice jams can also damage stream channels and improvements so that overall vulnerability to flooding is increased.

After a few days of warm temperatures, ice will begin to melt and can create flows of partially broken ice or ice jams that complicate the flooding potential by acting as a dam, obstructing the flow of water downstream. These ice jams can create rapid release of water, creating flash flooding in affected areas.

In many northern regions ice covers the rivers and lakes annually. The annual freeze up and break up commonly occur without major flooding. However, some communities face serious ice jam threats every year, while others experience ice jam induced flooding at random intervals. Ice jams have been reported most frequently in Montana and New York.

Although the actual time period of flooding may be short compared to open water flood events lasting days to weeks, significant damage and loss of life can result.

Ice jams in the United States cause approximately $125 million in damages annually, including an estimated $50 million in personal property damage and $25 million in operation and maintenance costs to USACE navigation, flood control, and channel stabilization structures. Ice-jam-related damage to river training structures costs millions of dollars each year.

For more details on ice jam flooding and their impact go to: http://www.crrel.usace.army.mil/icejams/ or http://www.noaawatch.gov/themes/flooding2.php. (NOAA, USACE) 

Tropical Weather Outlook

No new activity (FEMA HQ)

Earthquake Activity

No new activity (FEMA HQ)

Preliminary Damage Assessments

No new activity (FEMA HQ)

Disaster Declaration Activity

The President signed Major Disaster Declaration FEMA-1887-DR for the State of South Dakota on March 10, 2010 for Severe Winter Storm that occurred January 20-26.  The declaration provides for Public Assistance for 29 counties and those portions of the Cheyenne River Indian Reservation, Sisseton-Wahpeton Indian Reservation, and Standing Rock Indian Reservation that lie within those counties. All counties and Tribes within the State of South Dakota are eligible to apply for assistance under the Hazard Mitigation Grant Program. The FCO is Nancy M. Casper of the National FCO Program.(FEMA HQ)