NOAA Updates Spring Flood Risk Assessment

North central U.S., eastern Midwest and Ohio River Valley hold risk level for an extreme other than drought this summer

Published on: Mar 26, 2013

Just a few months ago, the word "flood" was not in the farm industry vernacular. But as strong storms pass through several key growing areas and soils recharge, flood risk begins to surface.

For some areas, drought continues to hold steady, but according to the National Weather Service Spring 2013 Flood Risk Assessment released Thursday, the north central U.S., eastern Midwest and Ohio River Valley could be in for at least minor flood risk. NWS uses long-range analysis to determine overall flood potential.

Roham Abtahi of the NWS projects that the largest risk will be for the Red River of the North, and the Souris River in North Dakota. Both Devils Lake and Stump Lake may also be at risk of rising, covering roadways and farm access roads.

North central U.S., eastern Midwest and Ohio River Valley hold risk level for an extreme other than drought this summer
North central U.S., eastern Midwest and Ohio River Valley hold risk level for an extreme other than drought this summer

Further, the chance of flooding along the Red River – especially in the southern portion of the basin and near the northern border of Canada – is nearly 100%. Fargo, N.D., also has a near 100% chance of exceeding major flood stage of 30 feet and a 50% chance of exceeding a river level of 38 feet.

The Upper Mississippi River basin also has flood potential, affecting southern Wisconsin, northern Illinois and northern Missouri. NWS predicts flooding near the Milk River in Montana, the Big Sioux River in South Dakota, and the Little Sioux River in Iowa.

For a large portion of the eastern Midwest and Southern U.S., recent rain and precipitation events have boosted river and tributary levels. NWS' Abtahi says this will continue into the spring, though some flooding in the Ohio River Basin is normal for the region.

NOAA Updates Spring Flood Risk Assessment

Over the Southwest, flood threat is below normal due to drought. NWS points out that any flooding in the area would likely be a result of excessive rainfall in short time periods.

Projections for the Western U.S. cannot be accurately made in Mid-March due to snowpack, NWS says.

Improved long-range mapping may benefit FEMA, Army Corps

After last summer's significant drought in the Midwest and continuing drought in the Plains highlighting the importance of the nation's river commerce, the National Oceanic and Atmospheric Administration worked to create an experimental long-range flood risk map.

The Federal Emergency Management Agency and the U.S. Army Corps of Engineers expressed interest in the new mapping system, which curates information for the 3-month risk of minor, moderate, and major river flooding in one webpage. The information is based on NOAA Ensemble Streamflow Prediction forecasts which are generated for thousands of river and stream forecast locations across the nation, NOAA says.

With the new page, anyone can view flood risk, which is defined in three categories:

-Minor Flooding: minimal or no property damage, but possibly some public threat (e.g., inundation of roads).

-Moderate Flooding: some inundation of structures and roads near stream. Some evacuations of people and/or transfer of property to higher elevations.

-Major Flooding: extensive inundation of structures and roads. Significant evacuations of people and/or transfer of property to higher elevations.

The page is available here.

According to NOAA statistics, floods kill nearly 100 people per year. To avoid risk of personal injury or loss of life, the agency reminds the public to monitor flood conditions online, look into flood insurance, purchase a weather radio, prepare an evacuation route and never cross flooded roads.