Document Type


Publication Date



North Dakota, Cloud Modification Project, Weather Modification


North Dakota farmers’ interest in using weather modification to increase precipitation and reduce hail damage resulted in starting a managed cost-sharing program, the North Dakota Cloud Modification Project (NDCMP). The effectiveness of NDCMP to increase precipitation is evaluated using rain gauge observations from the National Weather Service (NWS) Cooperative Observer Program (COOP) and the North Dakota Atmospheric Resource Board Cooperative Observer Network (NDARBCON). Monthly and seasonal (June, July, and August) precipitation is averaged county wide to create single and double ratio statistics. Operational weather modification counties, McKenzie and Bowman, have only 1 of 8 double ratios below 1.0; however, rainfall increases in target regions are relatively small (< 12 %) compared to the monthly rainfall variability and not readily apparent as only 2 out of 8 double ratios have greater than 95 % One-Tailed Test significance above 1.0. The statistical analysis approach is constrained by lack of a robust control due to sparse rain gauge measurements before the start of NDCMP and the lack of an independent control area with similar precipitation patterns. Additional years of weather modification operations will likely not improve statistical results significantly; instead, program evaluations efforts should consider usage of numerical models. However, incorporation of rainfall prediction models into a program evaluation will likely require improvements to currently available models, or at least careful configuration for the program’s region.


Atmospheric Sciences


Tru-Chek Rain Gauge and Standard 8-inch Rain Gauge

Processing Level



Precipitation Evaluation of the North Dakota Cloud Modification Project (NDCMP) Using Rain Gauge Observations

File Types




Associated Publications

Tuftedal, Matthew E., et al. “Precipitation Evaluation of the North Dakota Cloud Modification Project (NDCMP) Using Rain Gauge Observations.” Atmospheric Research, Dec. 2021, p. 105996.


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Western North Dakota, USA

North Boundary

48.9 degrees

West Boundary

-105.3 degrees

East Boundary

47.8 degrees

South Boundary

45.4 degrees

Temporal Resolution

24 hr

Start Date

1-6-1950 12:00 AM

End Date

31-8-2018 12:00 AM