Half Moon Bay, CA
Local storm history & FEMA National Risk Index data
Half Moon Bay is rated Relatively High for overall natural hazard risk — higher risk than most US counties — based on FEMA's National Risk Index for San Mateo County, CA. The county's highest-rated hazards are earthquake, landslide, and inland flooding.
Storm events near Half Moon Bay
NOAA-recorded tornado, hail, and flood events within 25 miles of Half Moon Bay's center, 2016–2026 — the only hazards NOAA reports with exact coordinates, so these counts are specific to Half Moon Bay itself, not the whole county.
County-wide hazard risk
Every other hazard FEMA and NOAA track — including drought — is only scored at the county level. These are San Mateo County's FEMA National Risk Index scores, covering Half Moon Bay along with the rest of the county, not a Half Moon Bay-specific figure.
| Hazard | NRI score | Rating |
|---|---|---|
| Wildfire | 92 | Relatively Moderate |
| Inland Flooding | 98.4 | Relatively High |
| Coastal Flooding | 91.8 | Relatively High |
| Earthquake | 99.7 | Relatively High |
| Heat Wave | 91.6 | Relatively Moderate |
| Tornado | 30.6 | Relatively Low |
| Avalanche | — | Not Applicable |
| Cold Wave | 0 | No Rating |
| Drought | 92.1 | Relatively High |
| Hail | 11.4 | Very Low |
| Hurricane | — | Not Applicable |
| Ice Storm | — | Not Applicable |
| Landslide | 99.7 | Relatively High |
| Lightning | 68.2 | Relatively Moderate |
| Strong Wind | 20.6 | Relatively Low |
| Tsunami | 70.8 | Relatively Moderate |
| Volcanic Activity | — | Not Applicable |
| Winter Weather | 3.4 | Very Low |
Source: FEMA National Risk Index v1.20.0, December 2025. See the methodology page for definitions, or the full San Mateo County risk profile for disaster declarations, social vulnerability, and climate projection data.
Other cities in San Mateo County:
More on San Mateo County:
Frequently asked questions
What natural hazards is Half Moon Bay, CA at risk of?
Half Moon Bay is rated Relatively High for overall natural hazard risk by FEMA's National Risk Index — higher risk than most US counties. The highest-rated hazards for San Mateo County, where Half Moon Bay is located, are earthquake, landslide, and inland flooding.
What is Half Moon Bay's biggest natural hazard risk?
Earthquake is the highest-rated hazard for San Mateo County, where Half Moon Bay is located, scoring 99.7 out of 100 on FEMA's National Risk Index (rated "Relatively High").
Is Half Moon Bay a high-risk area for natural disasters?
Yes — Half Moon Bay carries higher risk than most US counties for overall natural hazard risk, per FEMA's National Risk Index rating of "Relatively High" for San Mateo County.
Has Half Moon Bay had tornadoes, hail, or flooding?
NOAA has recorded 30 hail, 194 inland flooding events within 25 miles of Half Moon Bay since 2016.