Updated spring flood outlook for Red River Valley

courtesy: KSAX-TV / CC BY-NC-ND 2.0

GRAND FORKS, N.D. (Valley News Live) With more snow in the forecast, a lot of people are worried about flooding this spring.

The National Weather Service in Grand Forks says March looks like a tough month.

The conditions have been rough and will likely stay like that with prospects for delayed thaw and continued excessive snowfall, through much of the month.

Officials say the threat for significant snowmelt flooding has further increased across the main-stem Red River and its sub-basins.

Above normal snowfall has occurred and is expected to continue.

The next two weeks should see more substantial snowfall, so that widespread, above normal runoff is likely.

The deep frost is still present, even deeper, and should limit snowmelt infiltration, though soils are dry enough to handle some melt runoff, if the thaw cycle allows.

Climate outlooks still indicate a later snowmelt and runoff cycle which increases our risk for rapid and/or rainfall enhanced runoff. With a hint of near normal conditions by late March, and perhaps thaw commencing.

The risk for significant snowmelt flooding has further increased, running well above long-term historical averages across the Red River and Devils Lake Basins (U.S. portions).

Key Snowmelt Flood Components:

1. Base Streamflow: Still frozen, with near normal north, slightly above normal south. USGS analyses indicate that the Red River and its ND and MN tributaries are thick ice covered and/or flowing within long-term normal ranges, between 25th and 75th percentiles north of Fargo. Some higher quartile flows, 76% to 95%, were noted south of Fargo.

2. Soil Moisture at Freeze-up: Above normal south, near normal central, below normal far north.

3. Frost Depth: Deeper than normal everywhere. Extreme cold late Dec-Feb has driven frost from 35 to 45 inches in most areas, with river-ice and lake-ice thicknesses near to above seasonal normal ranges.

** With ice mainly in the lower channels, Ice Jams should be more of a risk on tributaries, less on the mainstem Red **

4. Winter Snowpack/SWE: above/much above normal. Since Dec 1st, snowfall has run from 90-160 percent of normal - least in east-central ND and most from northcentral MN into the central and southern RRV. The water content (SWE) ranges from 2.5 to 4.0 inches across most areas – including the Devils Lake Basin.

5. Total Precipitation, Oct 1st to Mar 5th is High. Total precipitation (rain and snow-water) measured across the Basin from Oct 1st through Mar 5th ranged from 1-3 inches above the long-term normal for most of the central and southern Red River Basin… with much above normal precipitation (an inch or more) expected through the next 7 days.