Update on Missouri River Basin Conditions
Above-average temperatures melted most of the plains snowpack in the upper Missouri River basin. A few areas in central North Dakota have some snowpack, but the National Weather Service (NWS) reports that areas of eastern Montana and central Wyoming have less than an inch of liquid content in their remaining snowpacks.
Runoff from snow melt started in February and has already entered the reservoir system. The warm temperatures also released water from river ice, which contributed to higher than average February runoff amounts. The U.S. Army Corps of Engineers reports that more than 90 percent of the Missouri River reservoir flood storage capacity is available. That space will be used to capture water from plains snowpack, spring rainfall, and the runoff from the snowpack in the mountains in the upper basin. The Corps’ 2017 runoff forecast for the Missouri River Basin above Sioux City is 29.1 million acre feet – 115 percent of the average. (An acre foot is the amount of water needed to cover an acre of land one foot deep.)
With heavy snows in parts of the upper basin this winter, some people were concerned about possible flooding along the Missouri River this spring. The National Weather Service’s current flood outlook shows little or no chance of flooding along the Missouri River in North and South Dakota. NWS reports an increased risk of major flooding in the Devils Lake region, the Souris River, and the Red River in eastern North Dakota, but those watersheds are outside the Missouri River basin.
On the monthly North Central U.S. Climate Summary and Outlook Webinar on March 16, Martha Shulski, Nebraska State Climatologist, reviewed recent climate trends and looked forward to outlooks for the year. Shulski said this winter was the 6th warmest on record in contiguous United States. It was also the 8th wettest winter. While some areas were wet, areas of moderate drought are occurring in western South Dakota, south-central Nebraska, and southeastern Iowa. In the long term outlook, Shulski said it appears that an El Niño system may return later this year, which will influence weather patterns in the Midwest and across the nation. NWS will have more on that later this year.