Contra Costa County, California severe weather history spans 108 recorded events between 1983 and 2026. The dominant hazard is flood, accounting for 54.6% of all recorded events. It ranks #2,856 nationally and #38 in California.
108
Recorded events
0
Direct deaths
0
Direct injuries
$44.8M
Property damage
The record
What the Contra Costa County, California severe weather history record shows
Across the archive, Contra Costa County, California severe weather history averages 2.5 recorded events a year. The busiest stretch on record is the 2010s, with 61 events logged in that decade alone. Roughly 4 events fall before 1990 and 104 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The costliest is flood, with $44.3M in reported property damage. In total, 7 distinct hazard types appear in this county archive, each listed with its own dated record below.
By hazard type
Every hazard type recorded in Contra Costa County
| Hazard | Events | Deaths | Damage | Max | Span |
|---|---|---|---|---|---|
| Flood | 59 | 0 | $44.3M | 0 | 1996–2026 |
| Hail | 14 | 0 | $0 | 0.75 | 1983–2020 |
| Flash Flood | 12 | 0 | $100K | 0 | 1997–2000 |
| Debris Flow | 9 | 0 | $0 | 0 | 2017–2019 |
| Tornado | 5 | 0 | $275K | F0 | 1989–2010 |
| Heavy Rain | 5 | 0 | $60K | 0 | 2010–2017 |
| Thunderstorm Wind | 4 | 0 | $50K | 55 | 1994–2024 |
Decade by decade
Contra Costa County, California severe weather history by decade
Reporting practice changed over time — early decades are undercounted, not calmer.
Tornado tracks
Paths crossing this county
5 mapped tornado paths intersect this county: 5 touched down inside it and 0 crossed in from a neighbouring county. This comes from path geometry, not county-tagged reports.
| Date | Scale | Deaths | Injuries | Path length | Origin |
|---|---|---|---|---|---|
| 2010-01-23 | EF1 | 0 | 0 | 1.6 mi | Touched down here |
| 1998-12-05 | EF0 | 0 | 0 | 1.5 mi | Touched down here |
| 1998-02-19 | EF0 | 0 | 0 | 0.2 mi | Touched down here |
| 1989-09-18 | EF0 | 0 | 0 | 0.2 mi | Touched down here |
| 1989-09-18 | EF0 | 0 | 0 | 0.2 mi | Touched down here |
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.
A series of accidents occurred. A driver went off the roadway on eastbound SR 24 near Wilder Rd in Orinda; a car spun out of control on eastbound I-80 near Willow Avenue in Hercules; and a pair of multicar crashes were reported on SR 24 and I-680 near Walnut Creek.
A low topped super cell produced an EF0 tornado near Brentwood. The tornado crossed power lines and destroyed a utility pole (DI24, DOD4). An eyewitness described the tornado as high winds from swirling white cloud. The pole was twisted to the ground and the top one-third of the 40-foot pole was splintered. Fifty-five customers lost power at 12:54 p.m. PST.
Context
Risk, population and federal disasters
Very High
FEMA NRI risk rating
1,165,012
Population (ACS)
$867K
Median home value
21
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| Jan 14, 2023 | Flood | SEVERE WINTER STORMS, FLOODING, LANDSLIDES, AND MUDSLIDES | DR |
| Jan 9, 2023 | Flood | SEVERE WINTER STORMS, FLOODING, AND MUDSLIDES | EM |
| Mar 22, 2020 | Biological | COVID-19 PANDEMIC | DR |
| Mar 13, 2020 | Biological | COVID-19 | EM |
| Apr 1, 2017 | Flood | SEVERE WINTER STORMS, FLOODING, AND MUDSLIDES | DR |
| Mar 16, 2017 | Flood | SEVERE WINTER STORMS, FLOODING, AND MUDSLIDES | DR |
Quick answers
Frequently asked
How many severe weather events have been recorded in Contra Costa County, California?
108 events are on record between 1983 and 2026, causing 0 direct deaths and $44.8M in property damage.
What is the most common severe weather hazard in Contra Costa County?
Flood, with 59 recorded events — 54.6% of everything in the archive for this county.
How many tornadoes have crossed Contra Costa County?
5 mapped tornado paths intersect the county boundary; 5 of them touched down inside it. This is derived from path geometry, not county-tagged reports.
How many federal disaster declarations cover Contra Costa County?
21 federal disaster declarations from FEMA include Contra Costa County, each tied to a specific incident period.
How risky is Contra Costa County compared with the rest of the country?
FEMA's National Risk Index rates Contra Costa County as very high risk, placing it in the 99 percentile of its state for expected annual loss.
Where does the Contra Costa County, California severe weather history data come from?
Every figure is drawn from United States federal public-domain records: NOAA/NCEI Storm Events for the event archive, NOAA SPC SVRGIS for mapped tornado paths, FEMA for disaster declarations and risk ratings, and the U.S. Census for population context. Dates are shown in UTC and recent entries may still be revised by NOAA.
Nearby
Neighbouring counties
- Colusa County 35
- Del Norte County 47
- Calaveras County 47
- El Dorado County 238
- Butte County 179
- Fresno County 783
Cite this page
“Contra Costa County, California.” Severe Weather History. severeweatherhistory.com/county/california/contra-costa-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.