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Flood in Los Alamos County, New Mexico
13 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.
NCEI records 13 flood events in Los Alamos County, New Mexico, between 1950 and 2026, spread over 6 years.
August is the busiest month, with 6 of the recorded events. The last 20 years account for 7 events against 6 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 0.7% of the 1,880 flood events recorded in New Mexico; its 11.9 per 100 square miles compares with 1.5 statewide.
Compared with New Mexico
| Measure | Los Alamos County | New Mexico | US |
|---|---|---|---|
| Flood events since 1950 | 13 | 1,880 | 183,559 |
| Per 100 square miles | 11.9 | 1.5 | 5.2 |
| Per 10,000 residents | 6.7 | 8.9 | 5.5 |
| Deaths recorded | 0 | 51 | 2,961 |
| Busiest month | August | July | June |
By year
Seasonality
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Recorded events
All 13 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 |
|---|---|---|---|---|---|---|---|
| 12 Jul 2013 | Flash Flood | — | — | — | — | — | County |
| 11 Jul 2012 | Flash Flood | — | $50K | — | — | — | County |
| 11 Jul 2012 | Flash Flood | — | — | — | — | — | County |
| 21 Aug 2011 | Flash Flood | — | — | — | — | — | County |
| 21 Aug 2011 | Flash Flood | — | $6.0M | — | — | — | County |
| 3 Aug 2011 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2008 | Flash Flood | — | $10K | — | — | — | County |
| 11 Aug 2001 | Flash Flood | — | $100K | — | — | — | County |
| 2 Jul 2001 | Flash Flood | — | $3.5M | — | — | — | County |
| 28 Aug 2000 | Flash Flood | — | — | — | — | — | County |
| 16 Jul 2000 | Flash Flood | — | — | — | — | — | County |
| 28 Jun 2000 | Flash Flood | — | — | — | — | — | County |
| 2 Jun 2000 | Flash Flood | — | — | — | — | — | County |
Questions and answers
How many flood events has Los Alamos County had?
13 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 Los Alamos County?
12 Jul 2013 (Flash Flood). Records reach NCEI about 120 days after the month ends.
What was the most damaging flood event recorded in Los Alamos County?
The flash flood of 21 Aug 2011, with property damage estimated by NCEI at $6.0M.
How does Los Alamos County compare with New Mexico for flood?
11.9 events per 100 square miles against 1.5 statewide; the county holds 13 of the state's 1,880 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 1 Oct 2026. See the methodology, the Flood hub and the county page.