50
Recorded events
1
Direct deaths
0
Direct injuries
$6.6M
Property damage
Debris Flow in San Bernardino County, California: 50 recorded events between 2012 and 2025. The strongest on record measured 0. That places the county #4 nationally and #4 statewide for this hazard.
Decade by decade
Debris Flow in San Bernardino County, California: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for debris flow in San Bernardino County is the 2020s, when 30 of the county's 50 recorded events were logged. Comparing decades is useful for spotting active periods, but the earliest years are thin because systematic reporting for this hazard began later.
Within the San Bernardino County archive, debris flow makes up 3.0% of all recorded severe weather across 12 hazard types. Nationally the county sits at #4 for this hazard and #4 within California, putting it in the 99.1 percentile of all U.S. counties.
Seasonality
Events by month
Aug is the peak month for debris flow in San Bernardino County with 10 recorded events, while Jun is the quietest. Seasonality here is a property of the archive as much as the climate: reports cluster where population and spotter networks are densest.
Significant events
Deadliest on record
| Date | Location | Scale | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Sep 12, 2022 | FOREST FALLS | 0 | 1 | 0 | $6.0M |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Aug 26, 2025 | LUCERNE VLY | 0 | $0 |
| Sep 20, 2024 | EAST HIGHLANDS | 0 | $20K |
| Aug 20, 2023 | GLEN MARTIN | 0 | $0 |
| Mar 15, 2023 | CRESTLINE | 0 | $0 |
| Feb 25, 2023 | DEVORE | 0 | $0 |
| Feb 24, 2023 | FONTANA | 0 | $0 |
| Jan 5, 2023 | RUNNING SPGS | 0 | $0 |
| Dec 28, 2022 | MOONRIDGE | 0 | $0 |
| Nov 8, 2022 | YUCAIPA | 0 | $10K |
| Nov 8, 2022 | CRESTLINE | 0 | $0 |
Other hazards here
More from San Bernardino County
- Flash Flood 836
- Thunderstorm Wind 197
- Flood 160
- Heavy Rain 124
- Wildfire 90
- Hail 67
- Lightning 63
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Heavy rain from monsoonal thunderstorms resulted in a rock slide in the San Bernardino Mountains. Highway 18 was closed for approximately 4 hours between Big Bear Lake and Snow Valley due to numerous rock slides in the Arctic Circle. One vehicle was reported to be stuck on the highway because of a large boulder stuck underneath their car.
Heavy rain fell in and around the Apple/ El Dorado burn scar on November 8, resulting in debris flow flooding. Roadway flooding was reported on Oak Glen Road and Potato Canyon Road at 12099 Oak Glen Road. El Dorado burn scar and flood prone area has had many prior flash floods and debris flows.
California Highway Patrol reported a mudslide along Highway 18 northeast of Big Bear City that was 6 feet deep and extending 20 feet across the highway. 12 vehicles were stranded in the mudslide. Highway 18 was closed between Big Bear and Lucerne Valley due to the debris flow.
Quick answers
Frequently asked
How many debris flow events are on record in San Bernardino County, California?
50 debris flow events are recorded in San Bernardino County between 2012 and 2025, causing 1 direct deaths.
What is the strongest debris flow recorded in San Bernardino County?
The strongest debris flow on record in San Bernardino County measured 0.
Where does the debris flow data for San Bernardino County come from?
All events come from the NOAA/NCEI Storm Events Database, the federal public-domain archive of severe weather reports. Dates are UTC, damage is as reported and not inflation-adjusted, and the most recent entries may still be revised.
Cite this page
“Debris Flow in San Bernardino County, California.” Severe Weather History. severeweatherhistory.com/county/california/san-bernardino-county/debris-flow/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.