美国国家气象局拉克罗斯分局于9月19日凌晨2点20分（美国中部夏令时）发布山洪警报,有效期至9月19日凌晨3点45分（美国中部夏令时）。
美国中部夏令时间凌晨2点20分，多普勒雷达和自动雨量计显示雷暴在预警区域内引发强降雨。降雨量在2至4.5英寸之间。还将出现更多降雨……
At 220 AM CDT, Doppler radar and automated rain gauges indicated thunderstorms producing heavy rain across the warned area. Between 2 and 4.5 inches of rain have fallen. Additional rainfall amounts up to 1.5 inches are possible in the warned area. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar and automated gauges.
IMPACT...Flash flooding of small creeks and streams, urban areas, highways, streets and underpasses as well as other poor drainage and low-lying areas.
Some locations that will experience flash flooding include... Preston, Spring Valley, Harmony, Mabel, Canton, Highland, Cherry Grove, Bristol, Newburg, Amherst, York, Carimona, Ostrander, Hutton, Granger, Forestville State Park, Greenleafton and Henrytown.
Affected area: Fillmore, MN