This alert expired on 28 June 2026 at 10:33 UTC. It is kept here as a record.
No stronger detection stands among the 37 recorded within 20 km of this point since 16 March 2026 — 9 others scored the same. Another comparable one was recorded here earlier the same day. 9 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued June 28 at 5:25AM CDT until June 28 at 5:30AM CDT by NWS Sioux Falls SD
An estimated 171,544 people live within 50 km of this point.
Nearby, since 16 March 2026
- July 2, 2026 · score 22 · 15.4 km
- July 26, 2026 · score 43 · 17.4 km
- August 11, 2026 · score 43 · 17.7 km
How we know
Confirmed by 5 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 90 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 43 / 100 |
| Our confidence | 90% |
| Coordinates | 43.2652, -96.3138 |
| Nearest City | Sioux Falls (45 km) |
| Population Exposed | 171.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-28T10:25:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.48e7d1e18e856b90e2c5e493ef918bbf |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Plymouth, IA; Sioux, IA; Lincoln, SD; Union, SD; Lyon, IA; Rock, MN; Lyon, IA; O'Brien, IA; Osceola, IA; Sioux, IA; Cottonwood, MN; Jackson, MN; Murray, MN; Nobles, MN; Pipestone, MN; Rock, MN |
| Headline | Severe Thunderstorm Warning issued June 28 at 5:25AM CDT until June 28 at 5:30AM CDT by NWS Sioux Falls SD |
| Expires | 2026-06-28T05:33:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.48e7d1e18e856b90e2c5e493ef918bbfab4b0b57.001.1","noaa_urn:oid:2.49.0.1.840.0.a8338711673050044151e370e69eff78dca260b4.001.1","noaa_urn:oid:2.49.0.1.840.0.9a54827cf596dd07c8d681376bc9c03c2684e7cd.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 60 |
| Iem Unit | MPH |
| Iem City | 4 E Irene |
| Iem County | Clay |
| Iem State | SD |
| Iem Wfo | FSD |
| MergedSources | [{"id":"iem_G_43.820_-96.780_1782639240000","source":"iem","severity":"low","severityValue":25,"timestamp":1782639240000,"latitude":43.82,"longitude":-96.78},{"id":"iem_G_43.580_-96.750_1782638520000","source":"iem","severity":"low","severityValue":25,"timestamp":1782638520000,"latitude":43.58,"longitude":-96.75},{"id":"iem_G_43.330_-96.880_1782639600000","source":"iem","severity":"low","severityValue":25,"timestamp":1782639600000,"latitude":43.33,"longitude":-96.88},{"id":"iem_G_43.080_-97.080_1782638820000","source":"iem","severity":"low","severityValue":25,"timestamp":1782638820000,"latitude":43.08,"longitude":-97.08}] |
Safety Information
Always follow official guidance from your local emergency management agency. This platform provides scientific monitoring data and is not a substitute for official warnings. If you are in immediate danger, contact your local emergency number.
Series begins 10 February 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Want to know when something happens in this area?
Calamity.live data shows a weather event with CalamityScore 43/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.