Santa Clara County Natural Disaster Statistics
FEMA rates Santa Clara County, California Very High for natural hazard risk, scoring 99.75 out of 100 on the National Risk Index. Santa Clara County carries an expected annual loss of $1.97 billion, and USGS assigns the surrounding San Francisco Bay region a 72% probability of a magnitude 6.7 or greater earthquake within 30 years. Earthquake is the county's dominant hazard by expected loss.
Key Santa Clara County Disaster Statistics
Federal primary data- FEMA rates Santa Clara County Very High for natural hazard risk, with a National Risk Index score of 99.75 out of 100. (FEMA National Risk Index v1.20)
- Santa Clara County ranks 9th of the 3,144 scored United States counties on the Risk Index. (FEMA NRI v1.20)
- 90% of California counties and 99.7% of United States counties score lower than Santa Clara County on the Risk Index. (FEMA NRI v1.20)
- Santa Clara County carries an expected annual loss from natural hazards of $1.97 billion. (FEMA NRI v1.20)
- Expected building loss in Santa Clara County is $1.57 billion per year, a rate of $1 lost per $243 of building value. (FEMA NRI v1.20)
- 15 of FEMA's 18 tracked hazard types contribute to expected annual loss in Santa Clara County. (FEMA NRI v1.20)
- USGS assigns a 72% probability of a magnitude 6.7 or greater earthquake in the San Francisco Bay region within 30 years. (USGS UCERF3)
- The same USGS forecast gives 51% for a magnitude 7.0 and 20% for a magnitude 7.5. (USGS UCERF3)
- Expected annual population loss in Santa Clara County is 28.68 fatalities, or 1 per 67,450 residents. (FEMA NRI v1.20)
- Santa Clara County scores 17.2 for social vulnerability (Very Low) and 72.6 for community resilience (Relatively High). (FEMA NRI v1.20)
- The 1989 Loma Prieta earthquake, magnitude 6.9, killed 63 people across the San Francisco Bay region. (USGS)
How Santa Clara County Compares Nationally
FEMA NRI · County ReportMost natural disaster statistics published online are national. They report what happened across the whole United States, which is close to useless if the real question is what the exposure looks like on a specific street in Santa Clara County. This page reports hazard figures at the level a buyer, seller, or underwriter in Santa Clara County can act on. This page prioritizes primary government sources for hazard data and identifies the limited non-government sources used for market and post-NOAA national trend data.
How Risky Is Santa Clara County for Natural Disasters?
Santa Clara County is rated Very High for natural disaster risk by FEMA, with a National Risk Index score of 99.75 out of 100. Very High is FEMA's top band. Santa Clara County ranks 9th of the 3,144 scored United States counties. 90% of California counties and 99.7% of United States counties score lower than Santa Clara County.
FEMA's National Risk Index scores every United States county on a 0 to 100 scale combining expected annual loss, social vulnerability, and community resilience. Santa Clara County's expected annual loss component scores higher still, at 99.86.
Two factors work in Santa Clara County's favor and are already reflected in that composite. FEMA classifies the county's Social Vulnerability percentile as Very Low at 17.24 and its Community Resilience percentile as Relatively High at 72.61. Both are percentile positions within FEMA's index rather than direct measurements of how a community recovers; the methodology section below sets out what each component is built from. The Very High rating survives both adjustments, which is what makes it significant.
| Measure | Rating | Score | Vs. California counties |
|---|---|---|---|
| Risk Index | Very High | 99.75 | 90% score lower |
| Expected Annual Loss | Very High | 99.86 | 98% score lower |
| Social Vulnerability | Very Low | 17.24 | 14% score lower |
| Community Resilience | Relatively High | 72.61 | 23% score higher |
Source: FEMA National Risk Index, Santa Clara County community report, county FIPS 06085, National Risk Index v1.20, released December 2025. Methodology and version notes: FEMA National Risk Index product page. Underlying county table available from OpenFEMA.
| Rank | County | Risk Index | Expected annual loss |
|---|---|---|---|
| 1 | Los Angeles County, CA | 100.00 | $7,601,846,373 |
| 2 | Cook County, IL | 99.97 | $2,424,304,449 |
| 3 | Harris County, TX | 99.94 | $2,217,702,383 |
| 4 | Riverside County, CA | 99.90 | $2,265,637,643 |
| 5 | Maricopa County, AZ | 99.87 | $2,195,561,910 |
| 6 | San Bernardino County, CA | 99.84 | $2,075,099,789 |
| 7 | Orange County, CA | 99.81 | $1,926,466,710 |
| 8 | Alameda County, CA | 99.78 | $1,884,810,319 |
| 9 | Santa Clara County, CA | 99.75 | $1,965,273,928 |
| 10 | San Diego County, CA | 99.71 | $1,539,181,273 |
Source: FEMA National Risk Index county table, v1.20, December 2025. Six of the ten highest-scoring United States counties are in California.
FEMA released National Risk Index v1.20 in December 2025 and Santa Clara County's figures moved substantially. Expected annual loss rose from $1.22 billion to $1.97 billion, an increase of 61 percent. The building loss rate went from one dollar per $431 of building value to one dollar per $243. Social vulnerability fell from 37.14 to 17.24. Any page still reporting the earlier figures is citing the superseded version. This page reports v1.20.
What Is the Chance of a Major Earthquake in Santa Clara County?
USGS puts the probability of a magnitude 6.7 or greater earthquake in the San Francisco Bay region, which includes Santa Clara County, at 72% within 30 years. The probability is 51% for magnitude 7.0 and 20% for magnitude 7.5.
Earthquake is the hazard that dominates Santa Clara County's loss profile, and it is also the hazard the federal government forecasts most precisely. The figures below come from the USGS Uniform California Earthquake Rupture Forecast, version 3.
| Magnitude | Probability within 30 years | Comparable event |
|---|---|---|
| 6.7 or greater | 72% | 1994 Northridge, magnitude 6.7 |
| 7.0 or greater | 51% | 1989 Loma Prieta, magnitude 6.9 |
| 7.5 or greater | 20% | 1906 San Francisco, magnitude 7.9 |
Source: U.S. Geological Survey, earthquake probability for the San Francisco Bay area, drawn from the Uniform California Earthquake Rupture Forecast 3 fact sheet. Regional outlook to 2043: USGS Fact Sheet 2016-3020. Figures cover the San Francisco Bay region as a whole, not a single fault or a single address.
How this is calculated. USGS publishes 30-year probabilities of 72%, 51% and 20%. Other holding periods shown here are derived from those published figures by converting each to a constant annual rate and compounding it, which assumes the rate does not change over time. The USGS model itself is time dependent, so treat other horizons as an illustration of scale rather than as a USGS figure. Only the 30-year values are published by USGS.
A 72% regional probability is not a 72% probability for any given house. Shaking intensity at a specific parcel depends on distance to the rupture, soil type, and liquefaction susceptibility, all of which vary enormously inside Santa Clara County. Valley floor parcels on young bay sediment and hillside parcels on bedrock face materially different exposure to the same earthquake.
How Much Loss Does Santa Clara County Expect Each Year?
FEMA calculates a composite expected annual loss of $1,965,273,928 for Santa Clara County. Of that total, $1,569,181,490 is expected building loss, a rate of $1 lost for every $243 of building value per year.
Expected annual loss is not a forecast for any particular year. It is the long run average once rare, severe events are spread across time.
| Loss category | Expected annual loss | Rate |
|---|---|---|
| Buildings | $1,569,181,490 | $1 per $243 of building value |
| Population equivalence | $378,233,468 | 1 fatality per 67,450 people |
| Agriculture | $17,858,971 | $1 per $301 of agricultural value |
| Composite total | $1,965,273,928 | 94.4 national percentile |
Source: FEMA National Risk Index, Santa Clara County expected annual loss. Population equivalence converts expected fatalities and injuries to dollars using FEMA's standard valuation so they can be summed with property loss, as documented on the National Risk Index methodology page.
- Buildings79.8%
- Population equivalence19.2%
- Agriculture0.9%
Applies FEMA's county-wide building loss rate of $1 per $243 of building value. This is a county average across all hazards and all construction types. It is not a property-specific figure, not an insurance quote, and not a prediction for any single year.
The building loss rate is the figure worth carrying. At $1 per $243 of building value per year, a Santa Clara County home with $1.5 million of structure replacement cost carries roughly $6,173 of annualized expected hazard loss before insurance. That figure illustrates the scale of modeled countywide hazard loss. Insurers use their own underwriting and catastrophe models, so FEMA expected annual loss should not be treated as an insurance pricing formula.
Which Santa Clara County Cities Get a Flood Insurance Discount?
Ten of Santa Clara County's fifteen cities participate in FEMA's Community Rating System. Cupertino and Palo Alto are Class 6, corresponding to a 20% CRS discount for eligible policies in the Special Flood Hazard Area; eight cities are Class 7, corresponding to 15%. Five cities do not participate. Actual policy discounts can vary by location and NFIP rating rules.
Every city in Santa Clara County participates in the National Flood Insurance Program, so flood insurance is available county-wide. What differs is the Community Rating System class, a voluntary FEMA program rewarding floodplain management that exceeds the NFIP minimum. A lower class number earns a larger discount, from 5% at Class 9 up to 45% at Class 1 for eligible policies inside the Special Flood Hazard Area. Properties outside the Special Flood Hazard Area in the same community receive a smaller discount: 10% at Class 6 and 5% at Class 7. Santa Clara County itself is Class 10 and earns no discount, while ten of its cities do.
| City | FEMA Community ID | NFIP status | CRS class | CRS SFHA discount | Effective FIRM | Median sale price |
|---|---|---|---|---|---|---|
| Campbell | 060338# | Participating | Not in CRS | None | 02/19/14 | $1,920,000 |
| Cupertino | 060339# | Participating | Class 6 | 20% | 05/18/09 | $3,055,000 |
| Gilroy | 060340# | Participating | Class 7 | 15% | 05/18/09 | $1,100,000 |
| Los Altos | 060341# | Participating | Class 7 | 15% | 05/18/09 | $4,515,000 |
| Los Altos Hills | 060342# | Participating | Not in CRS | None | 05/18/09 | $5,475,000 |
| Los Gatos | 060343# | Participating | Not in CRS | None | 02/19/14 | $2,577,500 |
| Milpitas | 060344# | Participating | Class 7 | 15% | 02/19/14 | $1,315,000 |
| Monte Sereno | 060345# | Participating | Not in CRS | None | 02/19/14 | $4,668,000 |
| Morgan Hill | 060346# | Participating | Class 7 | 15% | 05/18/09 | $1,350,000 |
| Mountain View | 060347# | Participating | Class 7 | 15% | 05/18/09 | $1,852,500 |
| Palo Alto | 060348# | Participating | Class 6 | 20% | 05/18/09 | $3,510,000 |
| San Jose | 060349# | Participating | Class 7 | 15% | 02/19/14 | $1,402,000 |
| Santa Clara | 060350# | Participating | Class 7 | 15% | 02/19/14 | $1,690,000 |
| Saratoga | 060351# | Participating | Not in CRS | None | 02/19/14 | $4,100,000 |
| Sunnyvale | 060352# | Participating | Class 7 | 15% | 05/18/09 | $1,865,000 |
| Santa Clara County | 060337# | Participating | Class 10 | None | 02/19/14 | $1,648,944 |
Three of the five highest-priced cities in Santa Clara County earn no flood insurance discount at all. Los Altos Hills, at a median sale price of $5,475,000, Monte Sereno at $4,668,000 and Saratoga at $4,100,000 do not participate in the Community Rating System. Gilroy, at $1,100,000, earns 15 percent. The pattern is not an oversight. These are foothill cities with little mapped floodplain to manage, so there is limited CRS credit available to them, and their hazard exposure runs to wildfire rather than flood. A buyer comparing insurance costs across these cities should expect the tradeoff to run in the opposite direction.
Source: FEMA NFIP Community Status Book, California, report dated August 11, 2026, cross-checked against the California State Hazard Mitigation Plan Appendix P. Median sale price is from the MLSListings Inc. feed and resolves at build time. Discounts apply to NFIP policies within the community and are not an insurance quote.
How Often Has Santa Clara County Been Federally Declared a Disaster Area?
Santa Clara County has been covered by 25 federal disaster declarations since 1977, including the 1989 Loma Prieta earthquake, the 2020 SCU Lightning Complex fire, and four separate winter storm declarations in 2023.
Federal disaster declarations are issued per event and per county, so a declaration count measures federal response activity rather than the number of natural events that occurred. A single storm system can produce declarations across dozens of counties.
| Date | Declaration | Hazard | Event |
|---|---|---|---|
| 1989-10-18 | DR-845-CA | Earthquake | Loma Prieta earthquake |
| 1991-02-11 | DR-894-CA | Freezing | Severe freeze |
| 1998-02-09 | DR-1203-CA | Severe Storm | Severe winter storms and flooding |
| 2020-08-21 | FM-5338-CA | Fire | SCU Lightning Complex fire |
| 2020-08-22 | DR-4558-CA | Fire | Wildfires |
| 2023-01-14 | DR-4683-CA | Flood | Severe winter storms, flooding, landslides |
| 2023-04-03 | DR-4699-CA | Severe Storm | Severe winter storms, straight-line winds, flooding |
Source: OpenFEMA Disaster Declarations Summaries v2, retrieved August 11, 2026. Filtered to state CA, county FIPS 085. Seven of 25 shown. Across Santa Clara, San Mateo, Santa Cruz and Monterey counties combined, the 2020s have already produced 35 declarations, more than any complete prior decade. Two per county are COVID-19, and declaration frequency reflects federal response policy as well as hazard frequency; excluding COVID the 2020s still lead.
Source: FEMA public notice for major disaster declaration DR-4699-CA and the OpenFEMA Disaster Declarations Summaries API. Full historical declaration series resolves at build time.
How Does Santa Clara County Compare to National Disaster Trends?
The United States has recorded 426 separate billion-dollar weather and climate disasters since 1980, with combined losses above $3.1 trillion. 2023 set the record at 28 events, 2024 followed with 27, and 2025 recorded 23 events costing $115 billion.
| Period | Events | Notes |
|---|---|---|
| 2023 | 28 | Record annual total |
| 2024 | 27 | Second highest on record |
| 2025 | 23 | $115 billion total, third highest |
| Since 1980 | 426 | More than $3.1 trillion combined |
Source: U.S. Billion-Dollar Weather and Climate Disasters dataset, Climate Central. NOAA retired this product in May 2025 with no updates beyond calendar year 2024, per the official NOAA NESDIS notice of changes. The archived federal series through 2024 remains available at NOAA NCEI.
If a statistics page cites NOAA's National Centers for Environmental Information as the live source for billion-dollar disaster counts, its figures stop at calendar year 2024 at the latest, because the federal product was discontinued in May 2025. A page reporting a 2025 or 2026 count while crediting NOAA is reporting a number its cited source does not publish.
The largest single event in the 2025 series was the January Los Angeles wildfire complex at $61.2 billion, the costliest wildfire in United States history by roughly a factor of two. That event is a principal reason California wildfire insurance availability tightened statewide, including in Santa Clara County markets with no comparable fire history of their own.
Does Disaster Risk Affect Home Values in Santa Clara County?
In Santa Clara County transactions, hazard exposure often becomes immediately relevant through insurance availability, premiums and deductibles. This page does not attempt to isolate the independent effect of hazard risk on sale prices.
Hazard exposure enters a Santa Clara County transaction through insurance underwriting: availability, premium, and deductible structure, particularly for parcels inside a CAL FIRE Very High Fire Hazard Severity Zone or a FEMA Special Flood Hazard Area.
The practical consequence for a buyer is that hazard risk belongs in the insurance contingency rather than in a pricing argument. For a seller, a parcel with a clean hazard profile and a bindable policy quote in hand removes a contingency that increasingly delays closings. Current market conditions are tracked separately on the Santa Clara County market statistics hub page, and city level pricing on the Santa Clara County home price statistics page. Neighboring hazard profiles are covered on the San Mateo County natural disaster statistics Santa Cruz County natural disaster statistics andMonterey County natural disaster statistics pages, and the national picture on the United States natural disaster statistics page.
Sources: California Department of Insurance filings, CAL FIRE Fire Hazard Severity Zone designations, Cal OES MyHazards, and Aegis Luxury Real Estate closed transaction records from the MLSListings Inc. feed.
Frequently Asked Questions
Is Santa Clara County a high risk area for natural disasters?
Yes. FEMA rates Santa Clara County Very High for natural hazard risk, scoring 99.75 out of 100 on the National Risk Index. That is FEMA's top rating band. 90% of California counties and 99.7% of United States counties score lower.
Which natural hazard is the biggest threat in Santa Clara County?
Earthquake is the largest contributor to expected annual loss in Santa Clara County. The county sits in a region USGS assigns a 72% probability of a magnitude 6.7 or greater event within 30 years, and the density of valuable construction converts that shaking into large modeled losses. Wildfire ranks second and concentrates in the western foothills and southern county.
Do I need earthquake insurance in Santa Clara County?
Standard California homeowners policies exclude earthquake damage, so coverage is purchased separately, most commonly through the California Earthquake Authority. Whether the premium is worthwhile depends on structure type, foundation, and how much of a household's net worth sits in the property. This is a question for a licensed insurance agent, not a Broker.
How often has Santa Clara County received a federal disaster declaration?
Recent declarations covering Santa Clara County include the severe winter storms and flooding of January 2023 and April 2023, and the SCU Lightning Complex fire of August 2020. Declarations are issued per event and per county, so the count reflects federal response activity rather than the number of natural events that occurred.
Does natural disaster risk lower home values in Santa Clara County?
In Santa Clara County transactions, hazard exposure often becomes immediately relevant through insurance availability, premiums and deductibles. This page does not attempt to isolate the independent effect of hazard risk on sale prices. Hazard exposure becomes a pricing factor when a parcel sits in a Very High Fire Hazard Severity Zone or a FEMA Special Flood Hazard Area and insurance is difficult to bind.
Where does the data on this page come from?
FEMA's National Risk Index supplies county risk scores and expected annual loss. The USGS Uniform California Earthquake Rupture Forecast supplies earthquake probability. CAL FIRE supplies fire hazard severity zones, and the MLSListings Inc. feed supplies price data. Every source is listed with its release cadence in the methodology section below.
Official Sources for Santa Clara County Hazard Data
Every figure on this page can be checked at its origin. These are the primary agency records, not summaries of them.
Using these Santa Clara County figures
Journalists, researchers, students, and other sites are welcome to reproduce any statistic on this page. No permission is required. Please cite the page and link to the permanent URL so readers can check the figure against its source and see the current version.
Timothy Alston. "Santa Clara County Natural Disaster Statistics." Aegis Luxury Real Estate, DRE# 01328224, updated August 17, 2026. https://aegishomesre.com/santa-clara-county-natural-disaster-statistics/
https://aegishomesre.com/santa-clara-county-natural-disaster-statistics/
This URL does not change. The page is updated in place rather than republished, so a link placed today continues to resolve to the current figures. For data questions or a comment from a licensed Broker on Santa Clara County hazard exposure, contact Timothy Alston at aegishomesre.com/contact.
Methodology and Sources
| Source | Supplies | Cadence | Last verified |
|---|---|---|---|
| FEMA National Risk Index | Risk score and rating, expected annual loss, social vulnerability, community resilience, hazard-type breakdown | FEMA revision cycle, currently v1.20 | Aug 11, 2026 |
| FEMA NFIP Community Status Book | Per city NFIP participation, Community Rating System class, premium discount, effective FIRM date | FEMA revision cycle | Aug 11, 2026 |
| California State Hazard Mitigation Plan, Appendix P | Cross-check on California NFIP and CRS status | State plan cycle | Aug 11, 2026 |
| OpenFEMA Disaster Declarations Summaries | Federal disaster declaration history by county since 1953 | Continuous | Aug 11, 2026 |
| USGS UCERF3 | 30-year earthquake probabilities by magnitude, San Francisco Bay region | USGS model update | Aug 11, 2026 |
| Climate Central Billion-Dollar Disasters | National billion-dollar event counts and costs | Annual | Aug 11, 2026 |
| NOAA NESDIS Notice of Changes | Record of the May 2025 retirement of the federal billion-dollar disaster product | Static | Aug 11, 2026 |
| MLSListings Inc. | Median closed sale price by city and county | Continuous | Aug 11, 2026 |
Most hazard and disaster figures on this page come from government sources. Climate Central is used for the post-2024 billion-dollar disaster series because NOAA retired the federal product in May 2025 and Climate Central continues the same peer-reviewed series. MLSListings Inc. supplies the real-estate price figures used for local market comparisons. No figure on this page originates from a commercial data aggregator. Where a number is not yet resolved from its primary source it appears as an unfilled token rather than an estimate.
Timothy Alston
Timothy Alston is a licensed real estate Broker serving all 15 cities of Santa Clara County. This reference page is maintained as part of an ongoing Santa Clara County data series and is updated when its source agencies publish.