59
Recorded events
0
Direct deaths
0
Direct injuries
$44.3M
Property damage
Flood in Contra Costa County, California: 59 recorded events between 1996 and 2026. The strongest on record measured 0. That places the county #189 nationally and #24 statewide for this hazard.
Decade by decade
Flood in Contra Costa County, California: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flood in Contra Costa County is the 2010s, when 35 of the county's 59 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 Contra Costa County archive, flood makes up 54.6% of all recorded severe weather across 7 hazard types. Nationally the county sits at #189 for this hazard and #24 within California, putting it in the 93.5 percentile of all U.S. counties.
Seasonality
Events by month
Feb is the peak month for flood in Contra Costa County with 18 recorded events, while May 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.
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Jan 5, 2026 | GREENBROOK | — | $0 |
| Dec 22, 2025 | RICHMOND | 0 | $0 |
| Nov 13, 2025 | RICHMOND | 0 | $0 |
| Feb 13, 2025 | CHRISTIE | 0 | $0 |
| Feb 5, 2025 | WALNUT CREEK | 0 | $0 |
| Dec 29, 2024 | PINOLE | 0 | $0 |
| Dec 27, 2024 | ORINDA | 0 | $0 |
| Nov 23, 2024 | ORINDA | 0 | $10 |
| Nov 23, 2024 | EL CERRITO | 0 | $10 |
| Apr 5, 2024 | HERCULES | 0 | $10 |
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
During heavy rainfall, a 24 inch culvert failed and collapsed, opening up a 20 foot sinkhole on Tarabrook Drive. One lane of traffic could still get by the sinkhole. The Orinda City Council declared a state of emergency due to this large sinkhole.
The roof of a Big 5 Sporting Goods store in San Ramon caved in the early morning hours of the 27th after a main beam broke in the center of the store. Local officials from the San Ramon Valley Protection District stated that they believed heavy rain was a factor in the roof collapse. The collapse caused water and debris to flow into the Big 5; the Rite Aid pharmacy next door was also flooded. Nearby businesses in the shopping center were closed as a precaution.
Quick answers
Frequently asked
How many flood events are on record in Contra Costa County, California?
59 flood events are recorded in Contra Costa County between 1996 and 2026, causing 0 direct deaths.
What is the strongest flood recorded in Contra Costa County?
The strongest flood on record in Contra Costa County measured 0.
Where does the flood data for Contra Costa 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
“Flood in Contra Costa County, California.” Severe Weather History. severeweatherhistory.com/county/california/contra-costa-county/flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.