Dry March Leads To Reduction In Missouri River Basin Runoff Forecast

Mountain snowpack and soil moisture conditions below average, impacting 2026 water supply

Apr. 9, 2026 at 5:08pm

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A sweeping, atmospheric landscape painting in muted tones of gray, brown, and blue, depicting the vast, open expanse of the Missouri River Basin under a hazy, overcast sky. The river and its tributaries are barely visible, dwarfed by the overwhelming scale of the natural environment.The Missouri River Basin faces a challenging water supply outlook as below-average snowpack and dry conditions persist, underscoring the region's vulnerability to the impacts of climate change.St. Louis Today

The U.S. Army Corps of Engineers has announced that the updated 2026 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa, continues to be below average. March runoff in the basin was 56% of the average, and mountain snowpack is currently below the 30-year minimum accumulation, leading to a forecast of 69% of average runoff for the year.

Why it matters

The Missouri River Basin provides critical water resources for agriculture, industry, and municipal use across several states. Below-average runoff and snowpack levels can lead to water supply challenges and impact navigation on the Missouri River.

The details

The March runoff in the Missouri River Basin above Sioux City was 1.7 million acre-feet, 56% of the average. The 2026 calendar year runoff forecast above Sioux City is 17.8 million acre-feet, 69% of average. The mountain snowpack in the upper Missouri River Basin is accumulating at below-average rates, with the Fort Peck reach at 71% of average and the Fort Peck to Garrison reach at 65% of average. The Corps of Engineers will adjust system regulation based on the latest information and provide updates through monthly water management conference calls.

  • March runoff in the Missouri River Basin above Sioux City was 1.7 million acre-feet.
  • The 2026 calendar year runoff forecast above Sioux City is 17.8 million acre-feet.
  • Mountain snowpack in the upper Missouri River Basin is accumulating at below-average rates as of April 2.

The players

John Remus

Chief of the U.S. Army Corps of Engineers' Missouri River Basin Water Management Division.

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What they’re saying

“Runoff into the reservoir system was below average for the month of March and conditions across most of the basin remain dry. Mountain snowpack has decreased as well and is currently below the 30-year minimum accumulation. We are forecasting a below-average runoff year for the basin.”

— John Remus, Chief of the U.S. Army Corps of Engineers' Missouri River Basin Water Management Division

What’s next

The Corps of Engineers will continue to monitor basin and river conditions, including plains and mountain snow accumulation, and adjust system regulation based on the most up-to-date information. The next monthly water management conference call will be held on May 7 to provide updates to stakeholders.

The takeaway

The below-average runoff forecast and snowpack levels in the Missouri River Basin highlight the ongoing challenges of water resource management in the region. Careful monitoring and adaptive regulation will be crucial to ensuring adequate water supplies for agriculture, industry, and municipal use in 2026.