Palo Alto, CA— fire, flood & earthquake hazard information
Palo Alto is a city in Santa Clara County in the San Francisco Bay Area, covering about 24.1 square miles. This page summarizes what official government maps show for Palo Alto: CAL FIRE fire hazard severity zones, FEMA flood zones, state seismic hazard zones, dam inundation areas, airport noise contours, and air-quality indicators. Figures are the share of Palo Alto’s area that falls inside each mapped zone.
View Palo Alto on the interactive map → to check any specific address, free.
Wildfire hazard severity zones
Per CAL FIRE's Fire Hazard Severity Zone maps, 2% is in a High zone. The remainder of its area is outside currently designated zones.
| High severity zone | 2% |
FEMA flood zones
17% of Palo Alto lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 9% is in a coastal high hazard zone (V/VE); 73% is in the 0.2% annual chance (500-year) area. Federally backed mortgages in a Special Flood Hazard Area generally require flood insurance.
| Special Flood Hazard Area (100-yr) | 17% |
| Coastal high hazard (V/VE) | 9% |
| 0.2% annual chance (500-yr) | 73% |
Earthquake faults & seismic zones
The nearest mapped fault, the Monte Vista-Shannon fault zone, is about 0.1 mi (0.1 km) from the center of Palo Alto. 8 named fault traces in the USGS Quaternary fault database cross its boundary. 33% of its area is in a state-designated liquefaction zone of required investigation. 22% is in an earthquake-induced landslide zone. 3% falls within an Alquist-Priolo earthquake fault zone, where new construction requires a fault study.
| Nearest mapped fault | Monte Vista-Shannon fault zone — 0.1 mi (0.1 km) |
| Named fault traces crossing boundary | 8 |
| Liquefaction zone | 33% |
| Earthquake-induced landslide zone | 22% |
| Alquist-Priolo fault zone | 3% |
Dam inundation, aircraft noise & air quality
6% of Palo Alto lies within a state-reviewed dam-failure inundation area; 1% is inside an airport noise contour of 65 dB CNEL or louder; annual average fine-particle (PM2.5) concentration across its census tracts is 7.8 μg/m³, and its composite pollution burden ranks around the 46th percentile statewide.
| Dam-failure inundation area | 6% |
| Airport noise ≥65 dB CNEL | 1% |
| Annual PM2.5 (tract average) | 7.8 μg/m³ |
| Pollution burden percentile (statewide) | ~46 |
Frequently asked questions
- Is Palo Alto in a wildfire hazard severity zone?
- Per CAL FIRE's Fire Hazard Severity Zone maps, 2% is in a High zone. The remainder of its area is outside currently designated zones.
- Is Palo Alto in a FEMA flood zone?
- 17% of Palo Alto lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 9% is in a coastal high hazard zone (V/VE); 73% is in the 0.2% annual chance (500-year) area. Federally backed mortgages in a Special Flood Hazard Area generally require flood insurance.
- What earthquake faults and seismic zones affect Palo Alto?
- The nearest mapped fault, the Monte Vista-Shannon fault zone, is about 0.1 mi (0.1 km) from the center of Palo Alto. 8 named fault traces in the USGS Quaternary fault database cross its boundary. 33% of its area is in a state-designated liquefaction zone of required investigation. 22% is in an earthquake-induced landslide zone. 3% falls within an Alquist-Priolo earthquake fault zone, where new construction requires a fault study.
- How do I check a specific address in Palo Alto?
- Use the free sitelume interactive map at https://sitelume.com — search any Palo Alto address to see which mapped zones it falls in, layer by layer.
Nearby in Santa Clara County
Sources: CAL FIRE Fire Hazard Severity Zones; FEMA National Flood Hazard Layer; USGS Quaternary Faults; CGS Seismic Hazard Zones & Alquist-Priolo zones; Cal OES dam inundation maps; county ALUC noise contours; CalEnviroScreen 4.0. Area shares are computed against each place’s Census TIGER boundary (last computed 2026-07-24). Boundaries and zone designations change; always verify with the issuing agency.