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San Mateo County, California
Recorded hazard history: storm events since 1950, federal disaster declarations since 1953, flood insurance claims since 1978, and FEMA's risk index.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. NCEI storm records through 30 Jun 2026; OpenFEMA declarations refreshed 1 Oct 2026; NFIP claims as of 8 Sep 2026.
San Mateo County, California, has 178 weather events in the NCEI Storm Events record since 1950, most of them floods and flash floods.
That is 39.7 events per 100 square miles, above the California figure of 26.2, and 2.4 per 10,000 residents against 10.4 statewide.
19 events fall in the 12 months to 30 Jun 2026. NCEI attributes 9 deaths and 30 injuries to events in the county, with property damage estimated at $16M and crop damage at $20.
FEMA has designated the county in 24 federal disaster declarations since 1953; the most recent is Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, And Mudslides (major disaster, 3 Apr 2023).
National Flood Insurance Program policyholders in the county filed 1,110 claims since 1978, of which 714 were paid, totalling $20M (about $28K per paid claim). FEMA counts 3,346 residential flood policies in force.
FEMA's National Risk Index rates the county's overall risk as "Relatively High" and its expected annual loss as "Relatively High" ($740M a year across 18 hazards).
Compared with California and the United States
| Measure | San Mateo County | California | US |
|---|---|---|---|
| Recorded events since 1950 | 178 | 40,849 | 1,977,440 |
| Events per 100 square miles | 39.7 | 26.2 | 56.0 |
| Events per 10,000 residents | 2.4 | 10.4 | 59.6 |
| Events in the last 12 months | 19 | 1,233 | 62,008 |
| Deaths recorded by NCEI | 9 | 1,170 | 26,435 |
| Property damage (NCEI estimates) | $16M | $30B | $575B |
| NFIP claims per 1,000 residents | 1.5 | 1.4 | 8.1 |
| Average paid NFIP claim | $28K | $21K | $43K |
| Claims per 100 policies in force, last 10 years | 6.6 | 5.0 | 16.1 |
County-recorded events plus zone-recorded events whose forecast zone is named for the county. State and US rows include events recorded only by forecast zone. Rates use 2021 Census population and land area.
Events by decade
Trend: 128 events in the 20 years to 2025 against 45 in the 20 years before. Reporting practice changed in 1996 and again with automated reports in the 2000s, so decade totals measure the record as much as the weather.
Events by type
Hazard pages exist for hail, tornado, flood, wind and winter where the county has at least 10 recorded events. "Other" covers heavy rain, debris flow, dust, funnel clouds and similar reports.
Largest recorded events
| Date | Event type | Group | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|---|
| 14 Jun 2000 | Heat | Heat | — | — | — | 6 | 10 | Forecast zone |
| 13 Oct 2009 | Heavy Rain | Other | — | — | — | 1 | 3 | County |
| 3 Feb 1997 | Flash Flood | Flood | — | — | — | 1 | — | County |
| 11 Jan 1998 | Heavy Rain | Other | — | — | — | 1 | — | County |
| 2 Jan 1998 | Heavy Rain | Other | — | — | — | — | 12 | County |
| 14 Mar 2012 | Heavy Rain | Other | — | $50K | — | — | 5 | County |
| 31 Dec 2005 | Flood | Flood | — | $5.0M | — | — | — | County |
| 1 Jan 2006 | Flood | Flood | — | $5.0M | — | — | — | County |
| 13 Feb 2000 | Heavy Rain | Other | — | $2.0M | — | — | — | County |
| 4 Mar 2001 | High Wind | Wind | 71 mph | $1.0M | — | — | — | Forecast zone |
| 20 Mar 2005 | Tornado | Tornado | F1 | $800K | — | — | — | County |
| 24 Nov 2001 | High Wind | Wind | 63 mph | $550K | — | — | — | Forecast zone |
| 25 Feb 2004 | Flood | Flood | — | $500K | — | — | — | Forecast zone |
| 11 Dec 2014 | Flash Flood | Flood | — | $500K | — | — | — | County |
| 19 Mar 2000 | High Wind | Wind | 82 mph | $250K | — | — | — | Forecast zone |
| 2 Feb 1998 | Flash Flood | Flood | — | $200K | — | — | — | County |
| 30 Nov 1998 | High Wind | Wind | 58 mph | $100K | — | — | — | Forecast zone |
| 25 Jan 2008 | Flash Flood | Flood | — | $100K | — | — | — | County |
| 13 Oct 2009 | Heavy Rain | Other | — | $100K | — | — | — | County |
Ranked by deaths, then injuries, then NCEI's damage estimate. Deaths and injuries are NCEI counts (direct plus indirect); no personal details are recorded here.
Federal disaster declarations
| Declared | Number | Type | Incident | Title | Programs |
|---|---|---|---|---|---|
| 3 Apr 2023 | DR-4699 | Major disaster | Severe Storm | Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, And Mudslides | Public assistance |
| 10 Mar 2023 | EM-3592 | Emergency | Flood | Severe Winter Storms, Flooding, Landslides, And Mudslides | Public assistance |
| 14 Jan 2023 | DR-4683 | Major disaster | Flood | Severe Winter Storms, Flooding, Landslides, And Mudslides | Individual assistance, Public assistance |
| 9 Jan 2023 | EM-3591 | Emergency | Flood | Severe Winter Storms, Flooding, And Mudslides | Public assistance |
| 22 Aug 2020 | DR-4558 | Major disaster | Fire | Wildfires | Individual assistance, Public assistance |
| 20 Aug 2020 | FM-5336 | Fire management assistance | Fire | Czu Lightning Fire Complex | Public assistance |
| 22 Mar 2020 | DR-4482 | Major disaster | Biological | Covid-19 Pandemic | Individual assistance, Public assistance |
| 13 Mar 2020 | EM-3428 | Emergency | Biological | Covid-19 | Public assistance |
| 1 Apr 2017 | DR-4308 | Major disaster | Flood | Severe Winter Storms, Flooding, And Mudslides | Public assistance |
| 16 Mar 2017 | DR-4305 | Major disaster | Flood | Severe Winter Storms, Flooding, And Mudslides | Public assistance |
| 10 Sep 2010 | FM-2856 | Fire management assistance | Fire | Glenview Fire | Public assistance |
| 5 Jun 2006 | DR-1646 | Major disaster | Severe Storm | Severe Storms, Flooding, Landslides, And Mudslides | Public assistance |
| 3 Feb 2006 | DR-1628 | Major disaster | Severe Storm | Severe Storms, Flooding, Mudslides, And Landslides | Public assistance |
| 13 Sep 2005 | EM-3248 | Emergency | Hurricane | Hurricane Katrina Evacuation | Public assistance |
| 9 Feb 1998 | DR-1203 | Major disaster | Severe Storm | Severe Winter Storms And Flooding | Individual assistance, Public assistance |
| 4 Jan 1997 | DR-1155 | Major disaster | Severe Storm | Severe Storms, Flooding, Mud And Landslides | Individual assistance, Public assistance |
| 12 Mar 1995 | DR-1046 | Major disaster | Severe Storm | Severe Winter Storms, Flooding Landslides, Mud Flow | Individual assistance, Public assistance |
| 10 Jan 1995 | DR-1044 | Major disaster | Severe Storm | Severe Winter Storms, Flooding, Landslides, Mud Flows | Individual assistance, Public assistance |
| 11 Feb 1991 | DR-894 | Major disaster | Freezing | Severe Freeze | Individual assistance |
| 18 Oct 1989 | DR-845 | Major disaster | Earthquake | Loma Prieta Earthquake | Individual assistance, Public assistance |
| 21 Feb 1986 | DR-758 | Major disaster | Flood | Severe Storms & Flooding | Individual assistance, Public assistance |
| 9 Feb 1983 | DR-677 | Major disaster | Coastal Storm | Coastal Storms, Floods, Slides & Tornadoes | Individual assistance, Public assistance |
| 7 Jan 1982 | DR-651 | Major disaster | Flood | Severe Storms, Flood, Mudslides & High Tide | Individual assistance, Public assistance |
| 20 Jan 1977 | EM-3023 | Emergency | Drought | Drought | Public assistance |
Declarations in which FEMA designated this county, from the OpenFEMA Disaster Declarations Summaries (v2). DR: major disaster; EM: emergency; FM: fire management assistance. Programs show whether individual or public assistance was made available.
Flood insurance claims
| Year of loss | Claims | Paid claims | Amount paid | Average paid |
|---|---|---|---|---|
| 2026 | 1 | 0 | $0 | — |
| 2025 | 4 | 3 | $164,289 | $54,763 |
| 2024 | 2 | 0 | $0 | — |
| 2023 | 27 | 15 | $659,707 | $43,980 |
| 2022 | 97 | 82 | $5,964,247 | $72,735 |
| 2021 | 44 | 33 | $2,562,744 | $77,659 |
| 2020 | 7 | 1 | $137,352 | $137,352 |
| 2019 | 4 | 1 | $7,766 | $7,766 |
| 2018 | 6 | 4 | $118,238 | $29,559 |
| 2017 | 28 | 18 | $483,875 | $26,882 |
| 2016 | 20 | 15 | $195,215 | $13,014 |
| 2015 | 5 | 2 | $60,654 | $30,327 |
| 2014 | 35 | 32 | $1,144,053 | $35,752 |
| 2013 | 3 | 1 | $3,238 | $3,238 |
| 2012 | 15 | 8 | $95,269 | $11,909 |
| 2011 | 7 | 1 | $36,063 | $36,063 |
| 2010 | 18 | 9 | $88,825 | $9,869 |
| 2009 | 6 | 1 | $95,665 | $95,665 |
| 2008 | 14 | 8 | $95,218 | $11,902 |
| 2006 | 12 | 9 | $218,854 | $24,317 |
| 2005 | 17 | 15 | $1,261,716 | $84,114 |
| 2004 | 13 | 10 | $123,757 | $12,376 |
| 2003 | 2 | 1 | $18,817 | $18,817 |
| 2002 | 26 | 21 | $806,452 | $38,402 |
| 2001 | 14 | 7 | $43,738 | $6,248 |
OpenFEMA NFIP claims (v3, as of 8 Sep 2026), aggregated by year of loss; amounts are building, contents and increased-cost-of-compliance payments as recorded. Repetitive-loss counts from the NFIP Multiple Loss Properties file (2 Aug 2026); policies in force from the NFIP Residential Penetration Rates file (3 Aug 2026).
National Risk Index
| Hazard (NRI) | Risk rating | Expected annual loss |
|---|---|---|
| Earthquake | $497,298,534 | |
| Inland flooding | $212,257,173 | |
| Coastal flooding | $8,653,751 | |
| Tsunami | $7,209,616 | |
| Landslide | $4,439,139 | |
| Heat wave | $4,108,687 | |
| Drought | $2,327,404 | |
| Wildfire | $2,224,911 | |
| Tornado | $627,473 | |
| Lightning | $548,920 | |
| Strong wind | $222,247 | |
| Hail | $43,216 | |
| Winter weather | $2,709 |
FEMA National Risk Index, December 2025 release. Ratings are FEMA's relative comparison of counties; expected annual loss is FEMA's modelled estimate of average yearly building, population and agriculture loss. See how to read the NRI.
Hurricane and tropical storm passes
No HURDAT2 track at tropical-storm strength passes within 100 miles of the county's centre point (through the 2025 season).
ZIP codes with flood claims
- 94010 124
- 94044 122
- 94060 89
- 94080 86
- 94070 74
- 94063 67
- 94025 57
- 94030 55
- 94401 48
- 94062 43
- 94403 43
- 94028 34
- 94002 29
- 94066 29
- 94020 28
- 94015 24
- 94404 21
- 94019 15
- 94027 13
- 94402 13
- 94014 12
- 94061 12
- 94005 6
- 94038 5
- 94074 5
ZIP codes whose NFIP claims carry this county's code, with the number of claims. Five or more claims are needed for a ZIP page to be indexed.
Questions and answers
How often does it hail in San Mateo County, CA?
NCEI records 9 hail events in San Mateo County since 1950, in 5 different years; that is about 0.1 recorded events a year. 0 reports were golf-ball size (1.75 in) or larger.
Has San Mateo County had a tornado?
Yes. NCEI records 4 tornadoes in San Mateo County since 1950, 0 of them rated (E)F2 or stronger. Tornado deaths recorded: 0.
When was the last federal disaster declaration for San Mateo County?
3 Apr 2023: Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, And Mudslides, a major disaster declaration for severe storm. The county appears in 24 declarations since 1953.
How many flood insurance claims have been filed in San Mateo County, and how much was paid?
1,110 NFIP claims since 1978, 714 of them paid, for $20M in total. FEMA publishes these figures redacted and aggregated; individual properties are not identified.
Is San Mateo County in the National Risk Index's high-risk band?
FEMA's National Risk Index (December 2025) rates the county "Relatively High" for overall risk, "Relatively High" for expected annual loss, "Relatively Low" for social vulnerability and "Very High" for community resilience. These ratings are FEMA's relative comparison across all US counties.
How does San Mateo County compare with the rest of California?
39.7 recorded events per 100 square miles against 26.2 statewide, and 1.5 NFIP claims per 1,000 residents against 1.4. The comparison table on this page shows each measure beside the state and national figures.
Provenance
Storm events: NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026 (public domain). Declarations: OpenFEMA DisasterDeclarationsSummaries v2, refreshed 1 Oct 2026. Flood claims: OpenFEMA NfipClaims v3 as of 8 Sep 2026; NfipMultipleLossProperties v1 (2 Aug 2026); NfipResidentialPenetrationRates v1 (3 Aug 2026). Risk index: FEMA National Risk Index, December 2025. Hurricane tracks: NHC HURDAT2 through 2025. Population and area: US Census Bureau, 2021 vintage. Built 1 Oct 2026; see the methodology and corrections pages. Hazard hubs: Hail · Tornado · Flood · Wind · Winter.