Portola Valley, CA
How exposed is Portola Valley to wildfire?
Portola Valley's 2,580 buildings earn a 82nd-percentile wildfire-risk score nationally under USFS's model — in USFS's highest wildfire-risk band nationally. (Source: USFS's Wildfire Risk to Communities methodology.)
Fire likelihood alone (USFS's burn-probability figure) ranks Portola Valley at the 83rd national percentile — 1 points above its risk-to-structures score, a gap driven by how much is actually built there.
What "at risk" means for the buildings here
91.3% of Portola Valley's 2,580 buildings sit in USFS's Direct exposure zone, roughly 2,355 structures close enough to burnable vegetation for flame contact, not just embers — 8.7% fall in the Indirect, ember-only zone and 0% are Minimal.
How Portola Valley compares
Inside California, Portola Valley sits at just the 43rd percentile even though it scores 82nd nationally — the state's overall wildfire exposure is high enough to make this a relatively quiet corner of it. Among the 31,521 US communities USFS scores, Portola Valley ranks 5,764 for wildfire risk (1 is highest) and 6,138 by building count (1 is largest). Within California alone, it ranks 896 of 1,570 places by risk. See the full county-by-county picture for California on its state page.
Portola Valley and the insurance market
Because Portola Valley is in California, a wildfire-hazard disclosure is legally required before a sale closes here — unusual nationally, since only these two states mandate it. The state's FAIR Plan alone carried 668,609 policies by the end of 2025. Full detail in the disclosure-law guide.
What would actually reduce this score
With 91.3% of Portola Valley in Direct exposure, defensible-space clearing and ember-resistant construction (vents, Class-A roofing) address the exposure this page's own numbers describe, not a generic checklist. See the home-hardening guide.
More on how this number was built
Every one of the two percentiles behind Portola Valley's 5,764-place national rank traces to USFS's Wildfire Risk to Communities dataset — see the methodology guide. For more on what direct exposure implies beyond Portola Valley, see the exposure-zones guide.