Replay · DE20250620
Northern Plains derecho: the story
Jun 20, 21:00 UTC – Jun 21, 13:00 UTC. Radar, severe thunderstorm and tornado warnings, storm reports and ground stops, in order, with 308 links that show their evidence.
- 189 NWS warnings
- 394 storm reports
- 0 FAA airport programs
- 1 derecho track (SPC)
- 308 rule-based links
- 57,392 customers out at the peak, in Minnesota
- 481 radar frames
Chapter 1: Western Dakotas
Jun 20–21
- The derecho's line begins (Storm Prediction Center).Replay from here
- NWS Rapid City, SD issues the first Tornado Warning.Replay from here
Chapter 2: Hail
Jun 21
- The largest hail reported: 3.6 in at 10 N Buffalo, SD.Replay from here
Chapter 3: North Dakota
Jun 21
- The strongest measured gust: 111 mph at 1 E Luverne, ND.Replay from here
- Peak outages: 57,392 customers out of power in Minnesota. The most in one county: Beltrami County, MN, 22,981 out (79% of its customers) at 12:30 UTC.Replay from here
Chapter 4: The line ends
Jun 21
- The derecho's line ends, 742 mi from where it began.Replay from here
How we link records
| Rule | What it checks | Links |
|---|---|---|
| R4 solid | A storm report inside a warning polygon while it was in effect | 308 |
Solid lines mark rules that passed an independent check; dashed lines are context. Links are rule-based facts: each shows two records that overlap in place and time. How we know
Where this storm's data comes from
Every layer, the provider behind it and the period it covers.
| Layer | Provider | Period | Records |
|---|---|---|---|
| MRMS SeamlessHSR | NOAA/NSSL via Iowa Environmental Mesonet | Jun 20, 21:00 UTC – Jun 21, 13:00 UTC | 481 |
| NWS storm-based warning polygons | NOAA National Weather Service via Iowa Environmental Mesonet | Jun 20, 21:00 UTC – Jun 21, 13:00 UTC | 189 |
| NWS Local Storm Reports | NOAA National Weather Service via Iowa Environmental Mesonet | Jun 20, 21:00 UTC – Jun 21, 13:00 UTC | 394 |
| SPC derecho table | NOAA Storm Prediction Center | Jun 20, 21:00 UTC – Jun 21, 13:00 UTC | 1 |
| ORNL EAGLE-I | Oak Ridge National Laboratory | Jun 20, 21:00 UTC – Jun 21, 13:00 UTC | 138 |
- Radar: NOAA/NSSL MRMS SeamlessHSR, via the Iowa Environmental Mesonet (IEM), Iowa State University
- Warnings: NOAA/NWS, storm-based polygons via the Iowa Environmental Mesonet
- Storm reports: NOAA/NWS Local Storm Reports via the Iowa Environmental Mesonet
- Airport programs: FAA Air Traffic Control System Command Center
- Derecho path: NOAA/NWS Storm Prediction Center derecho table (Squitieri et al. 2026)
- Power outages: Oak Ridge National Laboratory, EAGLE-I (CC BY 4.0)
- County boundaries: U.S. Census Bureau