Heavy Rains Soak Portions of Wilkin County 
August 28, 2002

Heavy rain produced by slow moving thunderstorms deposited five to six inches of rain onto portions of Wilkin county during the evening hours of Wednesday, August 28. The highest reported 24-hour rainfall total  was 5.50 inches in the city of Breckenridge. The heavy rain band was geographically isolated, covering a narrow band from just west of Wahpeton, ND to six miles east-northeast of Breckenridge. Rainfall totals in this five mile wide stripe exceeded four inches. An anectodotal report from Wahpeton claims seven inches of rain fell during the event. Urban flooding was reported in the Wahpeton/Breckenridge area. To demonstrate the highly variable spatial extent of the event, rainfall totals from other portions of the city of Breckenridge were less than three inches.

In the affected areas, a 24-hour rainfall total of six inches is considered to be a one percent probability occurrence.

National Weather Service radar imagery can be used to estimate precipitation totals in near real-time. A private vendor (WSI) purchases radar data from the National Weather Service and utilizes the data to prepare the precipitation estimates offered in the hyperlink below. Precipitation estimates from radar returns are often fraught with errors. Attenuation from heavy rain, enhanced reflection due to hail, and distance from the radar site, can cause radar-based estimates to over or under estimate true precipitation totals. For these reasons, this technology may never replace the need for ground-based precipitation measurements.

WSI radar-based precipitation estimate - 24 hour totals ending 7:00 AM, August 29

The State Climatology Office thanks Soil and Water Conservation Districts in the affected areas for their prompt and thorough response to our request for precipitation data. Data were also provided by the National Weather Service. We thank Minnesota's many volunteer precipitation monitors, whose diligent efforts make detailed analysis of storm events possible.

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URL: http://climate.umn.edu/doc/journal/flash_floods/ff020828.htm
Last modified: August 29, 2002