The Northern Plains remain wet, and it looks like this trend will not stop as winter sets in.
During a U.S. Army Corps of Engineers (USACE), Northwestern Division, Missouri River Water Management Division conference call Thursday, officials discussed the current state of a soggy basin.
Scott Dummer with the National Weather Service (NWS) said the past month has remained hydrologically active.
“We’ve had precipitation across the entire Missouri River basin and significant rainfall has occurred over northern Wyoming, Montana, South Dakota, south-central North Dakota and Missouri,” Dummer said. “Some of the locations have received in excess of 300% of normal precipitation for this period.”
He said some locations in Missouri have received upwards of 8 inches over the past month.
But it’s not just rain, according to Dummer.
“We’ve also developed an early-season snowpack over much of the upper basin, including Montana, Wyoming and the western Dakotas,” he said.
He said this snowpack has up to 4-5 inches of snow-water equivalent in some parts of the mountains of Montana and Wyoming.
Meanwhile, a storm system is expected to impact this region within the next week and could bring another inch of snow-water equivalent to that area.
Dummer said that flooding continues throughout parts of the Missouri River system.
“We have ongoing flooding in South Dakota in which we have minor-major flooding along the James River and minor flooding on the Big Sioux River at Watertown,” he said.
He said that once the next winter storm passes Wednesday, only light amounts of precipitation are expected in the upper basin the rest of the week.
The long-range forecast paints a grim picture.
“Unfortunately, the long-range outlooks favor the odds of a wetter-than-normal condition for the Missouri basin, at least through January, with a greater than 50% chance of major flooding in the James River basin,” he said.
Mike Swenson with the Missouri River Basin Water Management Division said that releases at Gavins Point Dam will remain at 80,000 cubic feet per second (cfs) into December, when they will be reduced to 22,000 cfs in the middle of the month.
John Remus, chief of the U.S. Army Corps of Engineers Missouri River Basin Water Management Division, said the Corps still aims to evacuate enough water from the system’s flood control zones before the 2020 runoff season.
“Given the basin conditions, our plan is to be as aggressive with the evacuation process this fall and again next spring in order to provide the greatest amount of flexibility in the system,” Remus said. “We will continue to evaluate the conditions on the ground and make adjustments as necessary.”
He added that officials anticipate they will make their goal.
“I am fairly confident we’ll be back at the base of the flood control zone by next year’s runoff season,” he said. “It’s not an arbitrary target; it’s something we aim for every year.”
USACE hydraulic engineer Kevin Stamm said the amount of runoff is forecast at 60.2 million acre feet. Currently, the system has seen 57.1 million acre feet in 2019 —the second highest amount in 121 years of record keeping — and second only to 2011 when the system saw 61 million acre feet of runoff.
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