By TOMMY REZAC
St. Joseph Post
The 2021 runoff forecast for the Missouri River Basin above Sioux City continues to be below average.
Doug Kluck, the NOAA Regional Climate Services Director for the Central Region, says plains and mountain snowpack is lagging behind seasonal averages, and soil moisture continues to be much drier-than-normal.
"Almost the entire Missouri River basin has some form of drought indicated across it," he said.
January 2021 runoff in the Missouri River Basin above Sioux City was 1.1 million acre-feet, or 141% of average. The above-average runoff was mainly due to above-normal temperatures melting plains snowpack and inhibiting river ice formation.
The 2021 calendar year runoff forecast above Sioux City is 89% of average. This forecast is based on soil moisture conditions, plains and mountain snowpack, and long-term precipitation and temperature outlooks.
Kevin Grode, the Reservoir Regulation Team Lead for the Missouri River Basin Water Management, says below-average runoff is expected through a good portion of the summer as well.
"We are forecasting below average runoff during each month of the March through July period," Grode said. "That period is considered the high runoff portion of the year."
Gavins Point Dam releases will be maintained at the winter release rate of 17,000 cubic feet per second, but will be adjusted if needed in response to ice formation on the Missouri River below the Dam.
Kevin Lau with the National Weather Service's Missouri River Basin Forecast Center, says ice jams are still a possibility, and spring thunderstorms could also cause flooding in some spots.
"Ice jam flooding remains a possibility throughout the winter," Lau said. "As we near the end of April, we have to be thinking about thunderstorm activity, which is the driver of springtime flooding."
Current studies indicate that flow support for Missouri River navigation will be at full service level for the first half of the 2021 season, which starts April 1 at the mouth in St. Louis.
You can follow St. Joseph Post on Twitter @StJosephPost.