767
Recorded events
45
Counties affected
52
Direct deaths
$882.7M
Property damage
California debris flow history: 767 recorded events across 45 counties between 1998 and 2026.
Decade by decade
California debris flow history by decade
The 2010s are the busiest decade on record with 425 reported debris flow events across California. Earlier decades are thinner because systematic reporting for this hazard expanded over time, not because the weather was calmer.
County ranking
Counties with the most debris flow events in California
| Rank | County | Events | Deaths | Damage | Span |
|---|---|---|---|---|---|
| #1 | Sonoma County | 60 | 0 | $16K | 2012–2025 |
| #2 | Kern County | 51 | 0 | $152K | 2016–2024 |
| #3 | Santa Cruz County | 51 | 0 | $117K | 2012–2025 |
| #4 | San Bernardino County | 50 | 1 | $6.6M | 2012–2025 |
| #5 | Fresno County | 40 | 0 | $200 | 2016–2025 |
| #6 | Monterey County | 32 | 0 | $10.1M | 2012–2025 |
| #7 | San Diego County | 30 | 0 | $2.1M | 2012–2024 |
| #8 | Mariposa County | 30 | 2 | $815K | 2017–2025 |
| #9 | Riverside County | 27 | 0 | $3K | 2014–2025 |
| #10 | Los Angeles County | 24 | 0 | $0 | 2018–2026 |
| #11 | Marin County | 24 | 0 | $2.0M | 2014–2021 |
| #12 | Santa Clara County | 24 | 0 | $0 | 2017–2021 |
| #13 | Mono County | 20 | 0 | $41K | 2014–2025 |
| #14 | Napa County | 19 | 0 | $0 | 2016–2021 |
| #15 | San Mateo County | 18 | 0 | $0 | 2017–2023 |
| #16 | Alameda County | 15 | 0 | $1K | 2012–2023 |
| #17 | Plumas County | 14 | 0 | $0 | 2012–2025 |
| #18 | Tulare County | 12 | 0 | $0 | 2017–2024 |
| #19 | El Dorado County | 11 | 0 | $6.5M | 2012–2021 |
| #20 | Alpine County | 10 | 0 | $0 | 2015–2025 |
| #21 | Orange County | 10 | 0 | $101K | 2015–2023 |
| #22 | Contra Costa County | 9 | 0 | $0 | 2017–2019 |
| #23 | Madera County | 8 | 0 | $5K | 2017–2025 |
| #24 | Santa Barbara County | 8 | 21 | $617.0M | 2018–2026 |
| #25 | Siskiyou County | 8 | 0 | $0 | 2014–2021 |
Significant events
Deadliest debris flow events in California
| Date | County | Scale | Deaths | Injuries |
|---|---|---|---|---|
| Jan 9, 2018 | Santa Barbara County | — | 21 | 168 |
| Dec 27, 2022 | Mariposa County | — | 2 | 0 |
| Feb 22, 2024 | Shasta County | — | 2 | 0 |
| Sep 12, 2022 | San Bernardino County | — | 1 | 0 |