Right now
The most recent data we hold from NOAA arrived 3 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
6 other detections within 20 km in the last 24 hours, the nearest <1 km from here.
This alert expired on 10 June 2026 at 08:00 UTC. It is kept here as a record.
It is the 7th strongest of the 254 detections recorded within 20 km of this point since 10 March 2026. The last comparable one was on 6 June 2026. 20 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Tornado Watch issued June 9 at 8:37PM CDT until June 10 at 3:00AM CDT by NWS Sioux Falls SD
Urban PEI: 181,553 within a heuristic 50 km radius; not unique people.
Nearby, since 10 March 2026
- September 15, 2026 · score 55 · 0.0 km
- September 14, 2026 · score 55 · 0.0 km
- September 6, 2026 · score 37 · 0.0 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 55 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) | 55 / 100 |
| Legacy data-support index | 0.81/1 |
| Coordinates | 42.0000, -93.2000 |
| Nearest City | Marshalltown (25 km) |
| Urban exposure index (PEI) | 181.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-10T01:37:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Tornado Watch_noaa_urn:oid:2.49.0.1.840.0.cadc4093e5951a1f6593276085969558 |
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: 2026-06-10T01:37:00.000Z.
First archived: 2026-06-10T03:40:34.937Z. 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 | Tornado Watch |
| Urgency | Future |
| Certainty | Possible |
| AreaDesc | Buena Vista, IA; Cherokee, IA; Clay, IA; Dickinson, IA; Ida, IA; Lyon, IA; O'Brien, IA; Osceola, IA; Plymouth, IA; Sioux, IA; Woodbury, IA; Cottonwood, MN; Jackson, MN; Lincoln, MN; Lyon, MN; Murray, MN; Nobles, MN; Pipestone, MN; Rock, MN; Dakota, NE; Dixon, NE; Beadle, SD; Bon Homme, SD; Brookings, SD; Clay, SD; Davison, SD; Hanson, SD; Hutchinson, SD; Kingsbury, SD; Lake, SD; Lincoln, SD; McCook, SD; Miner, SD; Minnehaha, SD; Moody, SD; Sanborn, SD; Turner, SD; Union, SD; Yankton, SD; Monona, IA; Antelope, NE; Boone, NE; Burt, NE; Butler, NE; Cedar, NE; Colfax, NE; Cuming, NE; Dodge, NE; Knox, NE; Madison, NE; Pierce, NE; Platte, NE; Saunders, NE; Seward, NE; Stanton, NE; Thurston, NE; Washington, NE; Wayne, NE |
| Headline | Tornado Watch issued June 9 at 8:37PM CDT until June 10 at 3:00AM CDT by NWS Sioux Falls SD |
| Expires | 2026-06-10T03:00:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | false |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.cadc4093e5951a1f659327608596955844ddd128.001.1","noaa_urn:oid:2.49.0.1.840.0.e76e1927d323327273941436ab05269e440d44ca.001.1"] |
Safety Information
If a tornado warning is issued: go to a basement or an interior room on the lowest floor, away from windows. A vehicle and a mobile home are not shelter. Cover your head and neck. Wait for the official all-clear before going outside, and watch for downed power lines and gas leaks afterwards.
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.
Review the area, threshold and delivery channel in your account.
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