Right now
The most recent data we hold from NOAA arrived 73 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 28 June 2026 at 10:30 UTC. It is kept here as a record.
It is the 9th strongest of the 43 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 3 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued June 28 at 4:43AM CDT until June 28 at 5:30AM CDT by NWS Sioux Falls SD
Urban PEI: 171,544 within a heuristic 50 km radius; not unique people.
Nearby, since 15 March 2026
- September 5, 2026 · score 37 · 8.7 km
- June 1, 2026 · score 67 · 11.5 km
- August 11, 2026 · score 43 · 13.5 km
How we know
4 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 43 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 43 / 100 |
| Legacy data-support index | 0.90/1 |
| Coordinates | 43.2331, -96.6969 |
| Nearest City | Sioux Falls (34 km) |
| Urban exposure index (PEI) | 171.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-28T09:43:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.c703e90e9a8fd7e08c173b5afd02e642 |
Physical priority index · v1. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-06-28T09:43:00.000Z.
First archived: 2026-06-28T10:00:05.771Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Lyon, IA; Rock, MN; Lincoln, SD; Minnehaha, SD; Turner, SD; Plymouth, IA; Sioux, IA; Clay, SD; Lincoln, SD; Union, SD |
| Headline | Severe Thunderstorm Warning issued June 28 at 4:43AM CDT until June 28 at 5:30AM CDT by NWS Sioux Falls SD |
| Expires | 2026-06-28T05:30:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.c703e90e9a8fd7e08c173b5afd02e642c6a4fbcc.001.1","noaa_urn:oid:2.49.0.1.840.0.add6c9422bfa4010dc32b84fe09fcfeadc7125d0.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 61 |
| Iem Unit | MPH |
| Iem City | Canistota |
| Iem County | McCook |
| Iem State | SD |
| Iem Wfo | FSD |
| MergedSources | [{"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_43.600_-97.290_1782635940000","source":"iem","severity":"low","severityValue":25,"timestamp":1782635940000,"latitude":43.6,"longitude":-97.29}] |
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 8 March 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.
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