Right now
Nothing else has been detected within 20 km in the last 24 hours.
Reported by USGS Water Services today.
It is the only one we have recorded within 20 km of this point since 21 September 2026.
What the source measured
USGS Water Services reported: Flood Impact Statement from National Weather Service (CNRFC) NWS ID: KCVC1 "Overtopping occurs just upstream of the gage and canyon" | Gage height: 1479.52 ft | Ref. point: 13.10 ft
Urban PEI: 16,941 within a heuristic 50 km radius; not unique people.
This is the lowest gauge height we have recorded at this point, over 10 readings since 28 August 2026 — the previous range was 451 ft to 1,479 ft.
How we know
One source: USGS Water Services. Not yet confirmed by a second, independent source.
Our own score for this event is 56 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 v5. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | River Floods |
| Severity | Critical |
| Calamity Score (ours) | 56 / 100 |
| Legacy data-support index | 0.69/1 |
| Coordinates | 38.9286, -122.8437 |
| Nearest City | Clearlake (19 km) |
| Urban exposure index (PEI) | 16.9K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-21T09:07:10.392Z |
| Source | https://waterdata.usgs.gov/monitoring-location/11449500/ |
Physical priority index · v5. 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: nwis. Occurrence: 2026-09-21T09:07:10.392Z.
First archived: 2026-08-28T20:54:49.876Z. Material modification: 2026-09-21T09:12:23.665Z.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
2026-09-21T09:12:23.665Z · model_change
Index 56 → 56; severity critical → critical; version 4 → 5.
Score Breakdown
Technical Details
| SiteNo | 11449500 |
| StationName | KELSEY C NR KELSEYVILLE CA |
| FloodCategory | major_flooding |
| EstimatedSeverity | major_flooding |
| SeverityProvenance | calamity-rtfi-excess-v1 |
| GageHeight | 450.96 |
| RpElevation | 3.99 |
| Unit | m |
| OriginalGageHeight | 1479.52 |
| OriginalRpElevation | 13.1 |
| OriginalUnit | ft |
| SourceImpactThreshold | {"id":12138,"name":"BANK","value":13.100000381469727,"unit":"ft"} |
| RpName | BANK |
| NwsId | KCVC1 |
| StateCode | CA |
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.
Review the area, threshold and delivery channel in your account.
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