Riverside County, California

What hazards hit Riverside County most?

The most frequent records are high wind and dust records: 955 since 1996. The rank column places the county among California's counties by days with a record per 1,000 square miles of land over each hazard's complete period.

Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.

How many tornadoes has Riverside County had?

NOAA records 27 tornadoes in Riverside County from 1955 to 2022, the strongest rated F3, with 0 deaths and 4 injuries recorded in the county. That is 28th of 57 California counties by days with tornadoes per 1,000 square miles since 1950. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.

Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 27 tornadoes whose track touched Riverside County since 1950 (NOAA's county records number 27, the same count); along their whole tracks they killed 0 people.

Map of the strongest tornado tracks in California.

Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.

When was the last damaging storm in Riverside County?

The most recent record with damage, injuries or deaths is the September 18, 2025 flash flood ($20,000 in damage in 2025 dollars).

Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.

The deadliest and costliest records

Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.

Is it getting more frequent?

Records per decade for Riverside County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).

Heat in the 2010s: 108 records against 27 in the decade before, 108 of them forecast-zone records. Cells marked z rose mostly through zone records. The local National Weather Service office files these once per forecast zone, so a change in how it draws its zones or splits a storm into records moves this count as much as the weather does; read it beside the Riverside County days with a record above.

Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).

What time of year?

Records by month in Riverside County. The two busiest months are in violet.

Source: NOAA NCEI Storm Events Database, records by the month they began.

Federal disaster declarations for Riverside County

FEMA's register lists 66 declarations that include Riverside County: 31 major disasters, 5 emergencies and 30 fire management assistance declarations. Most were for fire (38) and flood (13).

The 40 most recent of 66 are listed; the CSV has every one.

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.

How many floods has Riverside County had?

NOAA's Storm Events Database holds 430 flood or flash flood records for Riverside County from 1997 to 2025, on 219 days, with 6 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Riverside County ranks 225th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $21.2 million on 1,636 claims filed in Riverside County; the most in one year was 340 in 1980. Claims count insured losses only: uninsured flood damage is not in this file.

Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.

FEMA's modeled risk for Riverside County

FEMA's National Risk Index rates Riverside County Very High overall, with an expected annual loss of $2.3 billion. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.

Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.

Counties that share a border with Riverside County

1. San Bernardino County 3,395
2. Riverside County 2,854
3. San Diego County 2,725
4. Orange County 1,090
5. Imperial County 635
6. La Paz County, AZ 430

Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.

Next

• Tornadoes in CaliforniaEvery California tornado since 1950 and the counties with the most per square mile
• High wind and dust storms in CaliforniaThe state's high wind and dust records, by county, year and month
• The California recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Riverside CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Riverside County's FEMA declarations (CSV)66 rows: every declaration that named the county, for your own analysis