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March 15, 2012
U.S. Spring Flood Risk Map for 2012. Read the full National Hydrologic Assessment.
Download here (Credit: NOAA)
For the first time in four years, no area of the country faces a high risk of major to record spring flooding, largely due to the limited winter snowfall, according to NOAA’s annual Spring Outlook, which forecasts the potential for flooding from April to June.
“We’re not forecasting a repeat of recent historic and prolonged flooding in the central and northern U.S., and that is a relief,” said Laura Furgione, deputy director, NOAA’s National Weather Service. “The severity of any flooding this year will be driven by rainfall more so than the melting of the current snowpack.”
The Ohio River basin including portions of Illinois, Indiana, and Kentucky, along with parts of Louisiana and Mississippi are the only areas with an above-normal risk of flooding as soil moisture and river levels are currently above normal. Additionally, odds favor above-average April rainfall for the Ohio River basin.
River and stream water levels are normal to below normal for most of the country and there is less snow pack than in previous years. As a result, there is a normal flood risk from the Northeast, through the mid-Atlantic, across most of the northern Plains and into the Northwest. However, heavy spring rainfall can lead to flooding at any time, even in areas where overall risk is considered at or even below normal.
Above-average temperatures this spring are most likely from the Desert Southwest through the central and southern Great Plains, the Great Lakes, and the Eastern U.S., while the Pacific Northwest and Alaska are favored to be cooler than average. For precipitation, odds favor drier-than-average conditions mainly in the West and parts of the Southeast. Hawaii is favored to be relatively cool and wet.
U.S. Seasonal Drought Outlook for 2012.
Download here (Credit: NOAA)
Drought Outlook and Water Supply
Supported by the temperature and precipitation outlook, drought forecasters say drought conditions should persist across much of the southern U.S. and expand in the Southwest through spring. But improvement is possible from the southern and central Plains to the southern Appalachians, in the upper Midwest, and the Northwest. The Southwest is moving into the dry season, which should reduce chances for relief.
“Recent rainfall has helped lessen the drought in eastern Oklahoma, northeast Texas and interior Louisiana, but the historic magnitude of this prolonged drought means that recovery will be slow,” said David Brown, Ph.D., director, NOAA Southern Region Climate Services. “Drought is now encompassing parts of the West and Southwest making conditions more favorable for wildfires.”
The 2011 drought had significant economic impacts especially in Texas, Oklahoma and New Mexico. If the drought persists as predicted, it will likely result in an active wildfire season, continued stress on crops and livestock due to low water levels, and an expansion of water conservation measures.
Fortunately eight of 11 western states are reporting that reservoir levels are at or above normal capacity due to last year’s record snowfall. However, according to NOAA’s Water Resources Outlook, which forecasts the volume of water to reservoirs, inflows are expected to dip below normal this spring due to low snowpack this year. Arizona, New Mexico and Oregon state reservoir levels are below normal.
Although flooding risks have subsided it is important to remember that weather can change quickly – from drought to flooding to severe weather, including outbreaks of tornadoes. People can stay abreast of day-to-day weather fluctuations, as well as lifesaving advisories, watches and warnings, by owning a NOAA Weather Radio All-Hazards receiver and visiting www.weather.gov and by visiting FEMA’s Ready.gov for safety information.
NOAA's National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. NOAA’s National Weather Service operates the most advanced weather and flood warning and forecast system in the world, helping to protect lives and property and enhance the national economy. Working with partners, NOAA’s National Weather Service is building a Weather-Ready Nation to support community resilience in the face of increasing vulnerability to extreme weather. Visit us online at weather.gov and on Facebook.
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