Red River Valley likely to see major snowmelt flooding as March forecast shows no mercy, weather service says
FARGO — Two winter storms bearing down on North Dakota and Minnesota over the next seven days are expected to increase flood threats, leaving the Red River Valley at the mercy of how fast moisture-packed snow melts this spring, National Weather Service meteorologists said Thursday, March 7.
Above-normal snowfall has hit the region and is expected to continue into an “unmerciful” March, meteorologists said in an updated spring flood outlook. Two storms — the first on Saturday afternoon and the second likely Wednesday — are forecast to pummel the valley.
“The risk for significant snowmelt flooding has further increased, running well above long-term historical averages across the Red River and Devils Lake Basins,” meteorologists said.
Above-normal moisture, snowpack and frost depth are not extreme yet, but the two storms could push moisture levels much higher, weather service meteorologist Greg Gust said.
“The spring thaw cycle is running late, and that favors a fast thaw cycle as we get later into March and early April,” he said, adding that the overall risk for flooding is up.
However, precipitation levels ahead of the 1997 and 2009 floods were between 5 and 7 inches throughout the valley. “We have nothing near those levels yet,” Gust said.
The Red River in Fargo likely will reach a crest of at least 31 feet deep, above the major flood level of 30 feet, according to the weather service. There's a 50 percent chance the Red could be almost 35 feet deep, and a 5 percent chance of reaching 39 feet, just short of the record crest of 40.8 feet in 2009.
The city would start building temporary clay levees after the river hits 35 feet, while sandbagging could start after 37 feet, said Nathan Boerboom, an engineer for the city of Fargo. Fargo officials will watch the forecast closely and prepare as potential hazards develop.
Fargo already has tallied 49 inches of snow this season, above the normal of 37.5 inches for this time of year. But that's well below the total snowfall record of 83.4 inches for the 1996-97 season.
It's also below the 51.4 inches Fargo saw up to this point in the 2008-09 season. The total for that winter was almost 80 inches.
Wahpeton has a 25 percent chance of seeing major flooding, but the Red should crest there at about 12 feet, according to projections. The record there was set in 1997 at 19.4 feet, but there is only a 5 percent chance the Red will hit 17.5 feet in Wahpeton.
Southeast North Dakota and west-central Minnesota — mostly south of Interstate 94 — are at the greatest risk of seeing more than 6 inches of snow this weekend, according to the weather service.
“The greatest chance for 8 inches or more looks like just north of the North Dakota-South Dakota border, with again that highest potential around the Twin Cities down through Sioux Falls,” WDAY meteorologist Summer Schnellbach said.
A winter storm watch is in effect from early Saturday morning through Sunday afternoon for southeast North Dakota and west-central Minnesota, the weather service said. Winds could gust as high as 45 mph in some places.