Ag Weather Forum

A look at snowpack water content during winter is one way of keeping track of dryness and drought. That is certainly true in the U.S. Northern Plains, where drought is in its eighth straight month going back to June of 2024 according to the U.S. Drought Monitor. The water content that's being supplied to the Missouri River illustrates that deficit in moisture.

The U.S. Army Corps of Engineers monitors the snowpack water equivalent (SWE) throughout many river basins across the country. In the Upper Missouri basin, the SWE is checked and updated at Fort Peck, Montana, and Garrison, North Dakota. Those two stations show below-average snowpack water content as of early January. In the river stretch above Fort Peck, the mountain SWE on Jan. 1, 2025, was measured at 5.4 inches -- 22% or almost one-quarter--below the 1991-2020 average. The Missouri River reach from Fort Peck to Garrison had a SWE total of 4.4 inches -- 33% or basically one-third--below the 1991-2020 average on Jan. 1.

Snowfall reports at Upper Missouri basin weather stations further point out the lack of snow versus average. For the entire snow season so far, the National Weather Service office at Bismarck, North Dakota, has had approximately 11 inches of snow, less than half the average of 22.5 inches by early January. In Montana, the Glasgow NWS office has recorded just 6.8 inches of snow for the entire season up to Jan. 7, 2025 -- only 37% of the average 18.2 inches at this point. The SWE amount reaches its peak in the Upper Missouri basin around April 17, so there's still time for snow moisture to build up. Nonetheless, the snowpack moisture is for now, not a big performer.

In contrast, the mountain SWE in the Platte River basin is near to above average at the start of this calendar year. The Corps of Engineers SWE measurement for the North Platte River basin on Monday, Jan. 6, 2025, was 7.8 inches or 91% of the 1991-2020 average. In the South Platte River basin, the SWE on Jan. 6 was measured at 5.9 inches, 106% of the 1991-2020 average. Colorado, of course, was in the track of late fall-early winter snows and thus has offered more moisture on average to the Platte system compared with the Upper Missouri locations. The North Platte usually reaches its peak SWE around April 10, and the South Platte SWE usually peaks at the end of April.

The big south-central and eastern U.S. winter storm that ramped up during the weekend of Jan. 4-5 left the Northern Plains cold and dry. While portions of the south-central Plains took in up to a foot or more of snow, the Northern Plains had barely an inch. Storms in late winter and spring will indeed need to be generous for the Upper Missouri basin to make up its snowpack moisture deficit.

Bryce Anderson can be reached at bryce.anderson@dtn.com

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