In advance of a deep mid-level trough pushing eastward out of the Rockies, a weakening line of thunderstorms moved northeast across the Northern Plains in the early morning hours. A large and dwindling stratiform area supported the development of a strong wake low with wind gusts as high as 70 to 75 mph in portions of southeast South Dakota as well as northwest Iowa.
Every event with a place to put it; 17 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS FSD wrote it up.
In advance of a deep mid-level trough pushing eastward out of the Rockies, a weakening line of thunderstorms moved northeast across the Northern Plains in the early morning hours. A large and dwindling stratiform area supported the development of a strong wake low with wind gusts as high as 70 to 75 mph in portions of southeast South Dakota as well as northwest Iowa. Sporadic tree and building damage were reported as well as numerous power outages, which left around 630 customers without power during the early morning hours along the Interstate 29 corridor in South Dakota and almost 1600 without power in parts of northwest Iowa.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sioux Falls, SD wrote its last area forecast discussion before the first event at May 18, 9:47 PM CST, 3 hours 43 minutes earlier.
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</html>The national radar mosaic for the moment the first event began.
11 strong wind, 6 high wind. Local standard time, as filed.
Sustained easterly winds reached 30 to 39 mph with gusts as high as 56 mph near Dixon and 51 mph near Dallas.
Sustained easterly winds reached 40 to 46 mph near Wagner with gusts as high as 60 mph 9 miles southwest of Platte.
Sustained easterly winds reached 40 to 47 mph with gusts as high as 71 mph at Kimball and 58 mph 4 miles south-southeast of Kimball.
Sustained easterly winds reached 35 to 42 mph with gusts as high as 64 mph near White Lake.
Sustained easterly winds reached 30 to 39 mph with gusts as high as 56 mph near Wanger.
Sustained easterly winds reached 30 to 34 mph with gusts as high as 47 mph near Tripp.
Sustained easterly winds reached 30 to 39 mph with gusts as high as 45 mph at Yankton.
Sustained easterly winds reached 30 to 39 mph with gusts as high as 56 mph near Mitchell and 49 mph near Mount Vernon.
Easterly winds briefly gusted as high as 58 mph near Lane.
Sustained easterly winds reached 30 to 36 mph with gusts as high as 56 mph near Parker.
Sustained easterly winds reached 30 to 34 mph with gusts as high as 50 mph 7 miles west-southwest of Beresford.
Sustained easterly winds reached 30 to 34 mph with gusts as high as 54 mph near Woonsocket and 51 mph near Letcher.
Sustained easterly winds reached 30 to 39 mph with gusts as high as 52 mph near Cavour.
Sustained easterly winds reached 30 to 36 mph with gusts as high as 49 mph at Sioux Falls.
Sustained easterly winds reached 30 to 39 mph with gusts as high as 53 mph at Tea and 7 miles east of Davis.
Sustained easterly winds reached from 30 to 40 mph and briefly gusted as high as 60 mph near Flandreau.
Sustained easterly winds reached from 30 to 40 mph and briefly gusted as high as 72 mph 4 miles east of Alcester, 63 mph 8 miles south-southeast of Alcester, 62 mph 7 miles southeast of Alcester, and 58 mph 8 miles north of Elk Point.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2025Every state in 2025This day in weather historyWarnings in South Dakota, May 2025
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-30. Each event’s entry at NCEI: 1266322, 1266375, 1266346, 1266366, 1266378, 1266418, 1266450, 1266400, 1266402, 1266437, 1266455, 1266405, 1266410, 1266427, 1266445, 1266461, 1266467.