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Flood in Lassen County, California
11 floods and flash floods events in the NCEI Storm Events record, 1950 to 2026. Event types counted: Flood, Flash Flood, Coastal Flood, Lakeshore Flood.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. Storm records through 30 Jun 2026.
Lassen County, California, has 11 flood events in the NCEI record since 1950, with at least one in 6 different years.
December is the busiest month, with 4 of the recorded events. The last 20 years account for 8 events against 3 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 0.2% of the 7,136 flood events recorded in California; its 0.2 per 100 square miles compares with 4.6 statewide.
Compared with California
| Measure | Lassen County | California | US |
|---|---|---|---|
| Flood events since 1950 | 11 | 7,136 | 183,559 |
| Per 100 square miles | 0.2 | 4.6 | 5.2 |
| Per 10,000 residents | 3.3 | 1.8 | 5.5 |
| Deaths recorded | 0 | 121 | 2,961 |
| Busiest month | December | January | June |
By year
Seasonality
2Feb
3Mar
0Apr
0May
0Jun
0Jul
1Aug
0Sep
0Oct
1Nov
0Dec
4
Recorded events
All 11 events, most recent first. Magnitude is hail size, tornado rating or wind speed as recorded.
| Date | Event type | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|
| 24 Dec 2025 | Flood | — | — | $1K | — | — | County |
| 22 Dec 2025 | Flood | — | — | — | — | — | County |
| 22 Dec 2025 | Flood | — | — | — | — | — | County |
| 24 Oct 2021 | Flash Flood | — | — | — | — | — | County |
| 9 Feb 2017 | Flood | — | $500K | — | — | — | County |
| 7 Feb 2017 | Flood | — | — | — | — | — | County |
| 8 Jan 2017 | Flood | — | — | — | — | — | County |
| 8 Jan 2017 | Flood | — | — | — | — | — | County |
| 28 Feb 2006 | Flood | — | — | — | — | — | County |
| 31 Dec 2005 | Flood | — | $5.0M | — | — | — | County |
| 18 Jul 2002 | Flash Flood | — | — | — | — | — | County |
Questions and answers
How many flood events has Lassen County had?
11 events in the NCEI Storm Events record between 1950 and 2026. Reporting of floods and flash floods became far more complete after 1996, so early decades undercount.
When was the last recorded flood event in Lassen County?
24 Dec 2025 (Flood). Records reach NCEI about 120 days after the month ends.
What was the most damaging flood event recorded in Lassen County?
The flood of 31 Dec 2005, with property damage estimated by NCEI at $5.0M.
How does Lassen County compare with California for flood?
0.2 events per 100 square miles against 4.6 statewide; the county holds 11 of the state's 7,136 recorded events.
Provenance
NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026, public domain. County-recorded events plus zone-recorded events whose forecast zone is named for the county (marked "Forecast zone"). Population and area from the US Census Bureau (2021). Built 30 Sep 2026. See the methodology, the Flood hub and the county page.