Report: Valley moisture level high
The return of colder weather means the spring melt is probably a few weeks away.
But when the melt comes, it will unlock moisture embedded in the snowpack in the southern Red River Valley that remains higher than it was at this point in 2009, the year of the record Red River flood in Fargo-Moorhead.
Still, a major ingredient of that flood, which crested at 40.84 feet in Fargo, was the record 4.62 inches of moisture that fell in March 2009, including heavy rain.
Last week's Presidents Day snowstorm deposited between a tenth of an inch to an inch of precipitation in the southern Red River Basin, with heavier amounts to the south, near the South Dakota border.
"There was quite a gradient to the moisture content of the snow that fell," said Mike Lukes, a hydrologist for the National Weather Service in Grand Forks.
That leaves Fargo-Moorhead with 3.6 inches of water in the snowpack. Wetter conditions prevail to the south, including 5 to 6 inches in Wahpeton, N.D., and 6 to 8 inches in Wheaton, Minn.
For comparison, at this time in 2009, moisture in the snowpack at Wahpeton was 4 to 5 inches, and 5 to 6 inches at Wheaton, Lukes said.
During the thawing weather that preceded the Presidents Day storm, on Feb. 21, the snowpack in the southern Red River Valley "ripened," achieving a slushy consistency when snow temperatures reached the freezing borderline.
But the snow refroze, covered by a thin crust of ice. "So we're going to have to reheat that snowpack," Luke said.
Typically, the spring thaw starts in late March in the Red River Valley, spreading north during the first week of April.
Forecasters hope to predict the thaw seven to 10 days in advance, to help communities prepare for the spring flood.
Outlooks continue to call for below-normal temperatures and above-normal precipitation. The next flood outlook is expected on Thursday.
Readers can reach Forum reporter Patrick Springer at (701) 241-5522