Enter any address in San Mateo County, California to see its FEMA flood zone
In San Mateo County, a mix of flood events, including flash floods and coastal floods, have been recorded over the past 30 years. Recent impactful weather systems in December 2025 caused widespread disruptions, including delays at San Francisco International Airport and power outages for hundreds of thousands of customers. During this period, tornado warnings were issued for coastal areas of San Mateo and Santa Cruz counties.
National Flood Insurance Program (NFIP) data indicates that properties in Zone A have experienced a significant number of claims, with an average payout of $19,396 and an average water depth of 1.5 feet. Properties in Zone X, though fewer in number, have seen higher average payouts of $25,148 with an average water depth of 7.7 feet. Homeowners in coastal areas, as well as those in Zone A and Zone X, should pay particular attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
52 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
San Mateo County, California has recorded 101 flood-related events since 1996 according to NOAA's Storm Events Database, including 32 flash floods and 63 river or area floods. The county has received 24 federal disaster declarations, 8 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1977–2023)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Severe Winter Storms, Flooding, Landslides, And Mudslides | Flood | Mar 9, 2023 |
| Severe Winter Storms, Straight-line Winds, Flooding, Landslides, And Mudslides | Severe Storm | Feb 21, 2023 |
| Severe Winter Storms, Flooding, And Mudslides | Flood | Jan 8, 2023 |
| Severe Winter Storms, Flooding, Landslides, And Mudslides | Flood | Dec 27, 2022 |
| Czu Lightning Fire Complex | Fire | Aug 20, 2020 |
| Wildfires | Fire | Aug 14, 2020 |
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Winter Storms, Flooding, And Mudslides | Flood | Feb 1, 2017 |
| Severe Winter Storms, Flooding, And Mudslides | Flood | Jan 18, 2017 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flood | Dec 25, 2025 | 0.00K |
| Flood | Dec 24, 2025 | 0.00K |
| Flash Flood | Dec 24, 2025 | 0.00K |
| Flood | Dec 22, 2025 | 0.00K |
| Flood | Nov 17, 2025 | 0.00K |
| Flood | Nov 13, 2025 | 0.00K |
| Flood | Feb 13, 2025 | 0.00K |
| Flood | Feb 4, 2025 | 0.00K |
| Flood | Dec 14, 2024 | 0.00K |
| Flood | Mar 6, 2024 | 0.00K |
Flood — Dec 25, 2025
A series of storm systems impacted the Bay Area and Central Coast from December 19 to 25th, impacting Christmas holiday travel across the region. The most impactful systems arrived on Christmas Eve and Christmas Day. Two tornado warnings were issued for the coastal regions of San Mateo and Santa Cruz counties based off radar indicated rotation. San Francisco International Airport reported delay...
Flood — Dec 24, 2025
A series of storm systems impacted the Bay Area and Central Coast from December 19 to 25th, impacting Christmas holiday travel across the region. The most impactful systems arrived on Christmas Eve and Christmas Day. Two tornado warnings were issued for the coastal regions of San Mateo and Santa Cruz counties based off radar indicated rotation. San Francisco International Airport reported delay...
Flash Flood — Dec 24, 2025
A series of storm systems impacted the Bay Area and Central Coast from December 19 to 25th, impacting Christmas holiday travel across the region. The most impactful systems arrived on Christmas Eve and Christmas Day. Two tornado warnings were issued for the coastal regions of San Mateo and Santa Cruz counties based off radar indicated rotation. San Francisco International Airport reported delay...
Flood — Dec 22, 2025
A series of storm systems impacted the Bay Area and Central Coast from December 19 to 25th, impacting Christmas holiday travel across the region. The most impactful systems arrived on Christmas Eve and Christmas Day. Two tornado warnings were issued for the coastal regions of San Mateo and Santa Cruz counties based off radar indicated rotation. San Francisco International Airport reported delay...
Flood — Nov 17, 2025
A low pressure system brought rain and winds to the Bay Area and Central Coast on November 16 and 17th. Special Marine Warnings and Special Weather Statements were issued due to isolated thunderstorms causing localized heavy rain and gusty winds. The main frontal rain band came through in the overnight hours, with isolated to scattered showers and some thunderstorms continuing into the 17th.
Source: NOAA National Weather Service Storm Events Database.
Source: OpenFEMA NFIP Individual Claims (2.25M records analyzed).
FEMA assigns flood zone designations to areas in San Mateo County, California:
AE High Risk — 1% annual chance of flooding. Insurance required.
VE Very High Risk — Coastal flooding with wave action.
X (Shaded) Moderate Risk — 500-year floodplain.
X Low Risk — Outside major floodplains.
Properties in San Mateo County, California that are in FEMA-designated Special Flood Hazard Areas (zones A and V) with federally backed mortgages are required to carry flood insurance.
Even outside high-risk zones, flood insurance is recommended. From 2014 to 2024, nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area.
Visit FloodSmart.gov to find an agent and get a quote.