Beneath an expansive and strong, flat ridge aloft, extreme surface-based moisture returned near a diffuse warm frontal boundary on July 26 and lasted into the afternoon of July 28. While this moisture and heat would eventually fuel the derecho during the evening hours of July 28, dangerous heat indices from 105 to 120 degrees were common.
Every event with a place to put it; 8 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.
Beneath an expansive and strong, flat ridge aloft, extreme surface-based moisture returned near a diffuse warm frontal boundary on July 26 and lasted into the afternoon of July 28. While this moisture and heat would eventually fuel the derecho during the evening hours of July 28, dangerous heat indices from 105 to 120 degrees were common.
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 Jul 27, 5:21 AM CST, 5 hours 39 minutes earlier.
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</html>The national radar mosaic for the moment the first event began.
6 excessive heat, 2 heat. Local standard time, as filed.
Dangerous heat index readings reached an afternoon peak on July 27 as high as 107 degrees near Mountain Lake.
Dangerous heat index readings reached an afternoon peak on July 27 as high as 111 degrees at Lakefield and 107 degrees near Round Lake.
Heat index readings reached an afternoon peak on July 27 as high as 104 degrees near Ivanhoe and 103 degrees near Hendricks.
Dangerous heat index readings reached an afternoon peak on July 27 as high as 112 degrees at Marshall, 109 degrees at Tracy, and 105 degrees at Taunton.
Heat index readings reached an afternoon peak on July 27 as high as 102 degrees at Slayton and 100 degrees near Dovray.
Dangerous heat index readings reached an afternoon peak on July 27 as high as 108 degrees near Rushmore.
Dangerous heat index readings reached an afternoon peak on July 27 as high as 105 degrees near Pipestone.
Dangerous heat index readings reached an afternoon peak on July 27 as high as 117 degrees near Hardwick, 112 degrees near Luverne, and 106 degrees near Beaver Creek and Magnolia.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2025Every state in 2025This day in weather historyWarnings in Minnesota, July 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 2026-10-01. Each event’s entry at NCEI: 1288615, 1288616, 1288617, 1288618, 1288619, 1288620, 1288621, 1288622.