Spring flooding still likely in Red River valley
A month ago, weather officials in North Dakota issued a pretty sobering outlook for the Red River Valley and Devils Lake Basin: There were pretty major chances of pretty major flooding in that area, with some record-high river levels based on the amount of snow that's fallen in that area this winter.
Now, there's good news and bad news: The good news is there hasn't been much snow over the last few weeks, keeping additional moisture at a minimum. The bad news is, though conditions have been spring-like in much of the nation's midsection the last week, winter's not over.
"We had relatively small amounts of additional precip since January 25, from .25 to .50 inches," says Gregory Gust, National Weather Service waring coordination meteorologist. "And this past week, we've had some melting and sublimation/evaporation of moisture, maybe .10 to .25 inches of liquid, so net gain has been low."
Above-normal temperatures over the last week or so have moved along melting of the existing snowpack, which Gust says has "become quite dense and compacted."
On the other hand, there's still a lot of moisture out there. Though the snowpack has visibly dwindled in some areas, in others it's just compacted, so it contains just as much moisture as before the warm spell. "The actual moisture from the snow is still present either in the dense snow, in the near soil layer or in the ditches. It has not gone away," Gust says.
Soil moisture levels and base streamflows are also both "very high," he adds. Both river and lake levels have been near record-high levels all winter.
Of most worry, Gust says, is what he sees ahead: More winter weather is on its way in the coming weeks, and with the current pattern, it looks like sub-freezing temperatures could persist through normal snowmelt weeks, meaning when the spring thaw does arrive for good, it could make things soggy in a hurry.
"Winter conditions are on the return, with a colder and snowier than normal pattern expected for the later part of February and beyond," Gust says. "With La Nina conditions expected to continue in the Pacific through early summer, an active weather pattern should persist well through the typical March-April snowmelt runoff period."
It all adds up to about the same chance of spring flooding in the Red River Valley as anticipated a month ago, Gust says.
"Overall risks have remained at or just slightly higher than previously reported. Still expecting better than 90% risk of major flooding all along the mainstem Red River," he says. "Still expecting a slight risk of reaching or exceeding flood of record in some locales along the Red."