Drought Status Update for the Missouri River Basin

Current Conditions for the Missouri River Basin

• According to the U.S. Drought Monitor, 32% of the states within the Missouri River Basin are in drought. Severe Drought (D2) persists in Kansas, Wyoming, Nebraska, South Dakota, North Dakota, and Montana, with Extreme Drought (D3) impacting portions of Montana, eastern Wyoming, and western South Dakota.  
• Conditions deteriorated in many areas of the basin over the summer season (Figure 1). The most severe drought conditions are found in the western half of the basin. 
• Below-normal summer precipitation was one driver of this deterioration in many areas (Figure 2). Large parts of Montana, Wyoming, Nebraska, eastern Colorado, and the western portion of South and North Dakota received 5–70% of normal precipitation over June–August. Some of the largest deficits were in Wyoming, Montana, and western South Dakota, where drought conditions worsened.  The exception is portions of Kansas and eastern parts of North and South Dakota, which received 100–200% of normal precipitation. 
• Somewhat warmer-than-normal maximum air temperatures over the long term (June - August) and short term (7 days) further drove deteriorating conditions across the western part of the basin (Figure 3). These high temperatures dried vegetation and decreased soil moisture, increasing the likelihood of additional drought development. 
• August runoff in the Missouri River Basin was 1.2 MAF (million acre-feet), 86% of average above Sioux City. Gavins Point winter releases will be at minimum rate. 

Western Parts of the Missouri River Basin Saw Large Drought Degradations Since June 4 

Key Takeaway:  The western half of the Missouri River Basin states saw drought degradation of 1-3 categories throughout the summer. Areas with drought improvement were very limited. 

Summer Precipitation Totals Were Mixed Across the Missouri River Basin

Key Takeaway: Precipitation totals were mixed across the Missouri River Basin over the summer. Large areas of the Basin received below-average to significantly below-average precipitation (below the 50th percentile), especially parts of Montana, Wyoming, western Nebraska, and western South Dakota. Some areas of the Dakotas saw precipitation totals greater than 130% of average due to some very heavy isolated rain events.  

Western Basin Sees Warmer-Than-Normal Temperatures for Summer and the Last Week

Key Takeaway: Late August was cool compared to the long-term average across North Dakota, South Dakota, and parts of Nebraska. Above-average temperatures occurred across the rest of the Missouri River Basin throughout summer. Exceptionally high temperatures occurred in Nebraska, South Dakota, Wyoming, Montana, and North Dakota as a high pressure system settled over parts of the High Plains in late August. 

Missouri River Basin Drought Impacts

• Below-normal precipitation and above-normal temperatures across the western part of the region this summer caused negative impacts on the agriculture industry. Pasture and range conditions deteriorated in areas with continued or worsening drought. These poor conditions are coupled with reduced soil moisture across most of the basin (Figures 4, 5, 6). Impacts included heat-stressed crops, grasses curing early, reduced or no second cutting of hay, removal of livestock from pastures early, weaning calves and selling livestock earlier than usual, reducing herd size, buying and feeding hay, and reduced surface water quantity and quality for livestock. 
• Nebraska experienced record-breaking temperatures during July 23–August 5, 2024. 
• Dry conditions in northeast Wyoming and southeast Montana fueled numerous wildfires, which consumed nearly 500,000 acres of rangelands and reduced air quality. The largest of these fires includes the Remington Fire (at over 196,000 acres as of September 2, 2024) and the House Draw Fire (at nearly 175,000 acres as of September 2, 2024). 
• The river runoff forecast for the Missouri River Basin is still below normal due to drought conditions in the western half of the Basin, and reservoir systems continue to release water to meet downstream navigational targets. 
• Poor precipitation timing and spotty or limited precipitation totals throughout the summer reduced crop yields for some producers in western North Dakota. 
• Portions of Montana saw fishing restrictions or closures to protect fish species amid high water temperatures. 
• According to the U.S. Army Corps of Engineers, the six mainstem Missouri River power plants generated 631 million kilowatt-hours (kWh) of electricity in July. Typical energy generation for July is 954 million kWh. These power plants are expected to generate 8.0 billion kWh this year, compared to the long-term average of 9.4 billion kWh.

Vegetation Is Drying Across the Western Basin

Key Takeaway: Large precipitation deficits and above-normal maximum temperatures led to significant vegetation drying across Montana, Wyoming, western parts of North Dakota and South Dakota, and Nebraska. Despite above-normal temperatures, recent rains in eastern South Dakota and Nebraska improved vegetation conditions.

Pasture and Range Conditions Deteriorated, Especially in Montana and Wyoming

Key Takeaway: Pasture and range conditions in Montana and Wyoming were affected by drought, with less than 20% reported as good to excellent. South Dakota and Nebraska report less than 40% of pasture and range in good to excellent condition. Pastures in North Dakota are faring better with 58% in good to excellent condition. Conditions in South Dakota and Nebraska deteriorated over the previous week due to above-average temperatures in late August. 

Soil Moisture Conditions Worsened Across the Basin

Key Takeaway: Below-normal precipitation and above-normal maximum temperatures have worsened soil moisture conditions across much of the Basin.  The recent heat wave in Nebraska and Kansas has  rapidly reduced soil moisture.

Poor Pasture Conditions in North Dakota 

Key Takeaway: Above-normal temperatures and dry conditions have resulted in vegetation curing early and poor pasture conditions.

Outlooks and Potential Impacts for the Missouri River Basin

• The NOAA Climate Prediction Center’s outlook for September 2024 shows an increased chance of above-normal temperatures across the basin. The warm temperatures are coupled with an increased probability of below-normal precipitation across the basin (Figure 8), further increasing the chance of drought degradation. 
• Through the end of September, the Climate Prediction Center’s Monthly Drought Outlook predicts that drought will likely persist in areas already in drought, with drought degradation likely in South Dakota and Nebraska. Drought improvement is not expected in the basin (Figure 9).
• The next three months (September–November) have increased chances of transitioning from El Niño–Southern Oscillation (ENSO) neutral to La Niña conditions. La Niña can cause cooler winter temperatures in the northern High Plains.   
• Combined with above-normal temperatures, below-normal precipitation could mean lower streamflows, reduced soil moisture, crop stress, and additional livestock impacts. The combination of hot and dry weather could hamper establishment of fall-planted crops such as winter wheat and cover crops, but could also help with drydown of fall-harvested grain corn. 

Increased Chances for Hotter and Drier Weather in September 2024

Key Takeaway: According to the National Weather Service Climate Prediction Center, there are increased chances of above-normal temperatures across all of the Missouri River Basin states during September 2024. Most of the region is predicted to see below-normal precipitation during September 2024.

Drought Predicted to Continue or Develop in September

Key Takeaway:  The Climate Prediction Center predicts drought conditions will likely persist across parts of Montana, Wyoming, North Dakota, South Dakota, and Nebraska, and will likely develop across parts of northern Nebraska, southern South Dakota, and western Iowa through the end of September. No drought improvement is forecasted for the basin.