North Dakota, Idaho at Increased Risk for Floods This Spring as Drought Worsens in Southern Plains, NOAA Says
Published: March 16, 2017
Major river flooding is forecast in northern North Dakota, while moderate river flooding is possible over southern Idaho, according to NOAA's spring outlook released Thursday. In addition, drought conditions are expected to expand across parts of the southern Plains this spring (April-June), causing drought to develop in northwest Texas and far eastern New Mexico.
California is also susceptible to additional flooding after a record-wet winter in many cities, due to snowmelt and the threat for more storms through the remainder of the wet season (November-April).
(MORE: 8 Reasons Why Rain Is a Big Deal in Southern California)
"If you're in northern North Dakota, or in the Snake River basin in Idaho, prepare for moderate to major flooding this spring," said Dr. Tom Graziano, director of NOAA's Office of Water Prediction. "Snowpack is heavy in the West and northern Plains, and if our long-term warm-up coincides with spring rains, already-saturated soils will not be able to absorb the increased water, which would lead to increased runoff and potential flooding."
Here are the flooding and drought outlooks for spring 2017.
NOAA is most concerned about major river flooding in northern North Dakota, including the Souris River, Devils Lake and the northernmost reaches of the Red River. According to NOAA's National Operational Hydrologic Remote Sensing Center, much of this area still has up to four inches of water equivalent locked into the snowpack as of Thursday.
When warmer temperatures and rain melt this snowpack, the frozen soil and already-saturated ground won't be able to absorb it, leading to runoff and potential flooding. Forecasters are most concerned with Devils Lake, where a near-record runoff is expected and could cause the lake to rise 3 to 4 feet. This would possibly exceed its record-high flood level from June 2011 when the lake reached 1,454.4 feet above mean sea level.
Spring flood risk defined by risk of exceeding minor, moderate and major flood levels.(NOAA)
Additionally, a moderate flood risk exists in central and southeastern Idaho's Snake River basin, which received its second-highest snowfall on record this winter. Rain storms have already led to rapid snowmelt and caused flooding in this region's lower elevations. Future precipitation and temperatures will determine the intensity and duration of the Snake River's flood threat April through June.
(MORE: The Heaviest Snowfall Records in the U.S.)
Due to record amounts of rain and snow during the winter, California and Nevada may also experience snowmelt flooding this spring. However, it remains too early for forecasters to determine the severity, as snowpack will likely continue to build in the weeks ahead.
Minor flooding may occur in parts of Minnesota and Wisconsin southward through eastern Texas, as well as in a narrow band across the Southeast and along the East Coast to southern Virginia. Additionally, minor flooding is possible in Maine and parts of New Hampshire.
Below-average precipitation was observed overall this winter in the Northeast and mid-Atlantic, so the flood threat there is low despite Winter Storm Stella dumping 3 to almost 5 feet of snow in mid-March.
(MORE: Top Snow Total from Winter Storm Stella Hits 58 Inches in Northern Vermont)
Since late February, there has been a gradual expansion of drought conditions in the southern Plains and Southeast. This is due to continued dry conditions, warm temperatures and seasonal-increased water demand from early-spring vegetation, which started to bloom nearly three weeks ahead of schedule.
This trend is anticipated to continue in parts of the southern Plains this spring, with drought development forecast for northwest Texas and far eastern New Mexico, NOAA says.
U.S. Seasonal Drought Outlook as of March 16, 2017.(NOAA)
On the opposite side of the spectrum, some areas in the northern High Plains, south-central Plains, Tennessee Valley, mid-Atlantic and Northeast are likely to see improved drought conditions. In addition, the start of Florida's wet season (May-October) favors improving conditions in the Sunshine State through at least June.
(MORE: Florida's Wet and Dry Seasons)
According to the U.S. Drought Monitor issued Tuesday, only 8 percent of California remains in drought in the southern part of the state. NOAA expects this portion of California to continue experiencing drought conditions, as the dry season will soon be setting in by April or May.
U.S. Drought Monitor as of March 14, 2017.(National Drought Mitigation Center)
The 13 percent of Arizona currently in drought is also expected to remain that way through the spring.
In the Southeast, drought is forecast to persist from Alabama to northern Georgia and upstate South Carolina, where it has been firmly entrenched for much of the past year.
MORE: First Signs of Spring in Each State
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