An assessment of extreme precipitation trends in the Missouri River Basin: Insights from three gridded precipitation data sets and climate indices analysis

Authors: GUPTA, CHANCHAL - University Of Nebraska; MAHMOOD, REZAUL - University Of Nebraska; Flanagan, Paul; ROY, TIRTHANKAR - University Of Nebraska; HAYES, MICHAEL - University Of Nebraska; CHEN, LIANG - University Of Nebraska

Submitted to: International Journal of Climatology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2025
Publication Date: 10/22/2025
Citation: Gupta, C., Mahmood, R., Flanagan, P., Roy, T., Hayes, M., Chen, L. 2025. An assessment of extreme precipitation trends in the Missouri River Basin: Insights from three gridded precipitation data sets and climate indices analysis. International Journal of Climatology. 46(1).Article e70163. https://doi.org/10.1002/joc.70163.
DOI: https://doi.org/10.1002/joc.70163

Interpretive Summary: This study uses three separate gridded meteorological datasets to investigate extreme precipitation changes within the Missouri River Basin. Using advanced statistics and indices designed by the Expert Team on Climate Change Detection and Indices (ETCCDI), this study investigates past and current changes in precipitation and extreme precipitation patterns to inform stakeholders of possible future flooding scenarios within the at-risk Missouri River Basin. Results show that extreme precipitation events have become more intense since 1981 within the Missouri River Basin. Further, an analysis of precipitation return levels (for example, a once in 50 year precipitation event) showed that the return levels have been increasing in magnitude, indicating an increase in frequency of larger extreme precipitation events. In addition, multi-day heavy precipitation events have been becoming more intense through the 1981 to 2022 period. Thus, this analysis shows an increased risk of large-scale floods across the Missouri River Basin in recent years. Lastly, the 33 investigations revealed that more extreme precipitation events are occurring while the number of precipitation events is not significantly changing, thus extreme precipitation events are occurring at the expense of low impact precipitation events. Overall, the results of this study show that extreme precipitation is playing a larger role in the hydroclimate of the Missouri River Basin compared to at the start of the study period. This study gives stakeholders in the Missouri River Basin information on the shifts in extreme precipitation and an indication of the future climate extremes that critical water infrastructure needs to be built to withstand if current trends in extreme precipitation continue. USDA is an equal opportunity provider and employer.

Technical Abstract: This study investigates the changing characteristics of extreme precipitation patterns in the Missouri River Basin (MORB) from 1981 to 2022, utilizing three well-known gridded daily precipitation datasets: CHIRPS, CPC, and ERA-5. Employing the Expert Team on Climate Change Detection and Indices (ETCCDI) climate indices and the Mann-Kendall test, the study analyzes mean and extreme precipitation characteristics. Results indicate a consistent increase in extreme precipitation, particularly in the southern part of the basin, with total precipitation showing an upward trend across the MORB. The daily maximum 1-day precipitation (Rx1 day) index exhibits both positive and negative trends, but positive trends dominate, while the daily maximum consecutive 3-day precipitation (Rx3 day) and monthly maximum consecutive 5-day precipitation (Rx5 day) indices show positive trends, suggesting an elevated risk of large floods. Return level (RL) values are obtained by employing the Gumbel distribution to model annual daily maximum precipitation considering two different historical time periods. The analysis of differences in daily annual maximum RL values between recent and historic periods revealed a significant increase in precipitation magnitudes for extreme precipitation events, indicating a rise in the frequency of heavy precipitation events in recent decades. A larger positive trend observed in the average intensity of precipitation (SDII) and the annual total precipitation on days with precipitation exceeding the 95th percentile (R95 PTOT) in the southern MORB is of concern, signaling increased susceptibility to flooding downstream. The findings emphasize the urgency for proactive flood management and resilient infrastructure planning to address escalating risks associated with extreme precipitation in the MORB. This research contributes valuable insights into the evolving nature of extreme precipitation, which are useful for informing climate resilience strategies. Continuous monitoring and further research are crucial for refining our understanding and enhancing proactive mitigation measures. USDA is an equal opportunity provider and employer.