Right now
The most recent data we hold from NOAA arrived 40 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 18 May 2026 at 01:45 UTC. It is kept here as a record.
It is the 40th strongest of the 82 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flood Warning issued May 16 at 8:35AM CDT until May 19 at 7:00PM CDT by NWS St Louis MO
Urban PEI: 44,089 within a heuristic 50 km radius; not unique people.
Nearby, since 15 March 2026
- May 18, 2026 · score 34 · 0.0 km
- May 17, 2026 · score 34 · 0.0 km
- May 15, 2026 · score 34 · 0.0 km
How we know
4 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 34 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) | 34 / 100 |
| Legacy data-support index | 0.89/1 |
| Coordinates | 38.5650, -89.3767 |
| Nearest City | O'Fallon (46 km) |
| Urban exposure index (PEI) | 44.1K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-16T13:35:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.6de3c1ce0283802f6a45bf053e849b7ed7b171cc.001.1 |
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: 2026-05-16T13:35:00.000Z.
First archived: 2026-05-17T01:17:45.132Z. 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 | Flood Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Clinton, IL |
| Headline | Flood Warning issued May 16 at 8:35AM CDT until May 19 at 7:00PM CDT by NWS St Louis MO |
| Expires | 2026-05-17T20:45:00-05:00 |
| SenderName | NWS St Louis MO |
| HasExactCoords | true |
| Iem TypeSummary | D |
| Iem City | Benton |
| Iem County | Franklin |
| Iem State | IL |
| Iem Wfo | PAH |
| Iem Remark | Several reports of dime to nickel sized hail and large branches down in the Benton vicinity. |
| MergedSources | [{"id":"iem_H_38.000_-88.920_1778958360000","source":"iem","severity":"low","severityValue":25,"timestamp":1778958360000,"latitude":38,"longitude":-88.92},{"id":"iem_H_38.000_-88.920_1778958300000","source":"iem","severity":"low","severityValue":25,"timestamp":1778958300000,"latitude":38,"longitude":-88.92},{"id":"iem_D_38.010_-88.920_1778958900000","source":"iem","severity":"low","severityValue":25,"timestamp":1778958900000,"latitude":38.01,"longitude":-88.92}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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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