295
Recorded events
3
Direct deaths
11
Direct injuries
$179.5M
Property damage
Flash Flood in Riverside County, California: 295 recorded events between 1997 and 2025. The strongest on record measured 0. That places the county #13 nationally and #2 statewide for this hazard.
Decade by decade
Flash Flood in Riverside County, California: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flash flood in Riverside County is the 2010s, when 139 of the county's 295 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 Riverside County archive, flash flood makes up 31.7% of all recorded severe weather across 12 hazard types. Nationally the county sits at #13 for this hazard and #2 within California, putting it in the 99.6 percentile of all U.S. counties.
Seasonality
Events by month
Aug is the peak month for flash flood in Riverside County with 72 recorded events, while Apr 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 |
|---|---|---|---|---|---|
| Oct 1, 2018 | MORTMAR | 0 | 1 | 0 | $50K |
| Dec 22, 2010 | QUAIL VLY | 0 | 1 | 0 | $0 |
| Mar 5, 2000 | DESERT HOT SPGS | 0 | 1 | 0 | $300K |
| Feb 14, 2019 | MURRIETA | 0 | 0 | 4 | $20K |
| Jul 14, 1999 | BANNING | 0 | 0 | 3 | $0 |
| Sep 30, 2018 | MECCA | 0 | 0 | 1 | $200K |
| Jan 22, 2017 | TEMECULA RNCH CAL AR | 0 | 0 | 1 | $0 |
| Jul 19, 2015 | DESERT CENTER | 0 | 0 | 1 | $50.0M |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Sep 19, 2025 | EAGLE MTN | 0 | $20K |
| Sep 18, 2025 | (BLH)BLYTHE ARPT | 0 | $0 |
| Sep 17, 2025 | CHIRIACO SUMMIT | 0 | $0 |
| Mar 13, 2025 | SAN JACINTO | 0 | $0 |
| Jul 14, 2024 | RANCHO MIRAGE | 0 | $20K |
| Dec 22, 2023 | RIMLON | 0 | $0 |
| Sep 2, 2023 | DURMID | 0 | $0 |
| Sep 2, 2023 | COACHELLA | 0 | $0 |
| Sep 1, 2023 | MORTMAR | 0 | $20K |
| Sep 1, 2023 | MECCA | 0 | $0 |
Other hazards here
More from Riverside County
- Thunderstorm Wind 168
- Flood 132
- Wildfire 96
- Heavy Rain 92
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Thunderstorms with very heavy rain developed across portions of eastern Riverside County during the evening hours on September 30th. The stronger storms produced intense rain that led to flash flooding to the southwest of Joshua Tree National Park and to the north of the Salton Sea. At 1925PST (2025 PDT) the California Highway Patrol reported that Box Canyon Road was closed at the Mecca Copia Trail due to flash flooding. Significant impacts were reported to have occurred further downstream. Major damage was reportedly done to the Box Canyon Road forcing the road to be closed for days. It was also reported that a man was swept to his death driving along Box Canyon Road between Interstate 10 and Highway 111. He was returning from a camping trip in Joshua Tree National Park. His damaged car was found by the road later the next day with no trace of the man to be found. A Flash Flood Warning was issued for the area at 1909MST and it remained in effect until 2215MST.
A 39 year old Menifee woman was driving south on Goetz Road when the car was swept off the road by swift runoff from the Salt Creek, where it flows into Canyon Lake. She was found dead in her car at the bottom of the lake several hours later.
Heavy rainfall of 3 to 6 inches occurred in 12 hours and up to 1 inch per hour rates. This was the most significant flash flooding and debris flows since the December 6, 2018 event. The Holy fire scar flooded and sent debris flows through Temescal Canyon road and into homes and over roadways. Riverside County reported up to 70 million dollars in flood control structure damage in the 8 canyons affected.
Quick answers
Frequently asked
How many flash flood events are on record in Riverside County, California?
295 flash flood events are recorded in Riverside County between 1997 and 2025, causing 3 direct deaths.
What is the strongest flash flood recorded in Riverside County?
The strongest flash flood on record in Riverside County measured 0.
Where does the flash flood data for Riverside 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
“Flash Flood in Riverside County, California.” Severe Weather History. severeweatherhistory.com/county/california/riverside-county/flash-flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.