This alert expired on 17 May 2026 at 07:15 UTC. It is kept here as a record.
It is the 8th strongest of the 27 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued May 17 at 12:09AM CDT until May 17 at 2:15AM CDT by NWS Omaha/Valley NE
Nearby, since 15 March 2026
- September 1, 2026 · score 16 · 14.4 km
- August 10, 2026 · score 22 · 19.4 km
How we know
Confirmed by 5 independent sources, including NOAA.
Our own score for this event is 22 out of 100, at 70 % 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) | 22 / 100 |
| Our confidence | 70% |
| Coordinates | 40.3244, -95.6849 |
| Nearest City | Bellevue (92 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-17T05:09:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.3d1c6d8957803cb0e92124610ef54678 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Gage, NE; Jefferson, NE; Saline, NE; Gage, NE; Saline, NE and 6 more areas |
| Headline | Flash Flood Warning issued May 17 at 12:09AM CDT until May 17 at 2:15AM CDT by NWS Omaha/Valley NE |
| Expires | 2026-05-17T02:15:00-05:00 |
| SenderName | NWS Omaha/Valley NE |
| HasExactCoords | true |
| MergedCount | 9 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.3d1c6d8957803cb0e92124610ef54678f15f29d3.001.1","noaa_urn:oid:2.49.0.1.840.0.9d6068d2ac916938f8b929f5c9a45f7a62e94e60.001.1","noaa_urn:oid:2.49.0.1.840.0.4db3f418fb2e52af230cb1d28014c94396835f06.001.1","noaa_urn:oid:2.49.0.1.840.0.aa5b94b07379a1b62976cb5f449c22f1b50b1b32.001.1","noaa_urn:oid:2.49.0.1.840.0.22b95fc5eedf6a449ffccd48ec66106f42e5f7b9.001.1","noaa_urn:oid:2.49.0.1.840.0.3e6eb56703da1210cb9390bb3aae3dc440a1b5ae.001.1","noaa_urn:oid:2.49.0.1.840.0.f4d525dfe4ffecae5276887cda6ea4b1f724e2b0.001.1","noaa_urn:oid:2.49.0.1.840.0.24555793b3a1ba8cc09263b5206952b754bbeef2.001.1","noaa_urn:oid:2.49.0.1.840.0.4e78f34e54504056a99e3f92a93e5ffe3ce94ca6.001.1"] |
| Iem TypeSummary | F |
| Iem City | 1 S Sterling |
| Iem County | Johnson |
| Iem State | NE |
| Iem Wfo | OAX |
| Iem Remark | Measured 3.10" so far. Flooding seen in fields and low lying areas. |
| MergedSources | [{"id":"iem_E_40.470_-96.500_1778989020000","source":"iem","severity":"low","severityValue":25,"timestamp":1778989020000,"latitude":40.47,"longitude":-96.5},{"id":"iem_F_40.460_-96.510_1778987760000","source":"iem","severity":"low","severityValue":25,"timestamp":1778987760000,"latitude":40.46,"longitude":-96.51},{"id":"iem_H_40.340_-94.870_1778979540000","source":"iem","severity":"low","severityValue":25,"timestamp":1778979540000,"latitude":40.34,"longitude":-94.87},{"id":"iem_F_40.450_-96.380_1778992260000","source":"iem","severity":"low","severityValue":25,"timestamp":1778992260000,"latitude":40.45,"longitude":-96.38}] |
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 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 22/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.