Wildfire Risk in Nevada County, CA 2026

Local context

A fire record that reads reassuringly — and shouldn't

Nevada County spans from the Sacramento Valley edge near Penn Valley, across the gold-rush foothill belt at Grass Valley and Nevada City, up over the Sierra crest to Truckee. Almost all of its population lives in the western third, in low-density housing scattered through continuous oak woodland and foothill pine. It is, in structural terms, one of the most thoroughly interfaced counties in the state — there is very little boundary between "town" and "forest" to point at. The California Department of Insurance, ranking counties by the share of homes sitting in high fire-risk exposure, placed Nevada County third statewide.

Now look at what the fire-history layer returns for an Alta Sierra parcel. Four mapped NIFC perimeters in total. One in the last twenty years.

Oak Fire (2018) — 9 acres.
Halcon Fire (2002) — 20 acres.
Newnan Lightning #9 (1960) — 739 acres.
Rattlesnake Fire (1951) — 586 acres.

That is a seventy-five-year record with nothing in it larger than a square mile. The county's benchmark event, the 49er Fire of September 1988 — roughly 33,700 acres and more than 300 structures across Rough and Ready, Penn Valley and Lake Wildwood — burned west of Grass Valley, outside the search radius of this particular parcel and now old enough that a recurrence-based score barely registers it. The resulting fire-history layer scores 20 / 100 — Moderate, the lowest layer in the whole report.

What the county has had since is small and quickly caught: the Jones Fire (August 2020) burned 705 acres and 18 structures in the Yuba River drainage northwest of Nevada City, and the Rices Fire (June 2022) burned 904 acres and four structures near Rices Crossing. Both were held to under a thousand acres. Neither tested the fuel bed that surrounds Grass Valley.

A quiet fire record is not evidence of safety. In a fuel type that carries fire every few decades, it is a statement about accumulated fuel and about how long it has been accumulating.

Flames running through oak woodland and brush during the 1988 49er Fire in Nevada County, California, with a CAL FIRE engine parked on the road in the foreground — The 49er Fire, Nevada County, 1988 — fire running through the same oak-woodland fuel type that still surrounds Grass Valley. Source: CAL FIRE, via Wikimedia Commons (public domain).

A destroyed home reduced to a chimney and rubble above a lake after the 1988 49er Fire in Nevada County, California, with a fire engine on the road beside the ruins — Structural loss in the 49er Fire, 1988 — the last time this fuel bed burned at scale near Grass Valley. Source: CAL FIRE, via Wikimedia Commons (public domain).

Sources: NIFC fire perimeters (via Satelife fire-history layer) · CAL FIRE Incident Archive.

Terrain & vegetation

Where the houses are the forest

Alta Sierra is the clearest example of the county's settlement pattern: a census-designated place of 7,204 residents spread across roughly 2,148 hectares of ridges and drainages south of Grass Valley, with parcels cut into standing timber rather than cleared from it. On satellite imagery the community is hard to distinguish from the forest around it — which is precisely the problem.

The LANDFIRE vegetation layer that feeds Satelife's fuel score makes the structure explicit. Across the community: 54.9% Mediterranean California mixed oak woodland, 7.0% lower montane foothill pine woodland and savanna, 5.2% dry-mesic chaparral — and 6.6% classified as "urban evergreen forest", the class LANDFIRE uses for developed land that still carries a closed evergreen canopy. That 6.6% is the built core of Alta Sierra, and the classifier is telling you it reads as forest.

LANDFIRE LF2024 vegetation-type map of Alta Sierra, Nevada County, showing the community boundary filled largely with green Mediterranean California mixed oak woodland and a violet core of urban evergreen forest where the housing sits under closed canopy — Vegetation type across Alta Sierra — LANDFIRE LF2024 Existing Vegetation Type, the same layer that produces the report's fuel score. The violet core is developed land that LANDFIRE still classifies as evergreen forest. Source: LANDFIRE LF2024 EVT · USGS / USDA Forest Service.

Terrain compounds it. The community sits on the broken ground between the Bear River and Wolf Creek drainages, and the terrain layer scores 65 / 100 on slope and aspect alone. The fire-weather layer — a thirty-year ERA5 climatology of the Canadian Fire Weather Index at this location — reads 65 / 100, materially hotter and drier than the 56 / 100 the same layer returns for Paradise in Butte County.

The Alta Sierra community boundary outlined on current satellite imagery south of Grass Valley, California, showing an unbroken dark green forest canopy inside and outside the boundary with only faint road lines revealing the subdivision — Alta Sierra on current satellite imagery. Inside the outline and outside it, the canopy is continuous — the road network is the only reliable way to see where the community is. Imagery © Esri, Maxar, Earthstar Geographics.

Evacuation

Twenty-nine exits, and twenty-nine hotspot zones

Satelife's community-scale analysis of Alta Sierra gridded 2,148 hectares into 346 analysis zones and rebuilt the access picture from the current road graph and OSM-mapped fire stations. On the headline egress measures the community does well:

29independent road exits from the analyzed area

11.9analysis zones per exit route

4.1 minmodelled fire-truck drive-time from Nevada County Consolidated Station 89 (2.24 km)

13–15 minmodelled drive-time to the community's top hotspot zones

Twenty-nine exits, seventeen stations within fifteen kilometres, no single-point bottleneck detected on the modelled network. The nearest station the model picks — Nevada County Consolidated Fire Station 89 on Tammy Way, beside the Alta Sierra golf course — is staffed around the clock and carries a Type III wildland engine alongside its structure engines, so the 4.1-minute figure is a real capability rather than an artefact of a mapped-but-volunteer station. Taken alone, that is a healthy egress profile — better than Grizzly Flats in El Dorado County, which returned nine exits and a 32-minute nearest-station drive-time.

The number that deserves attention is a different one. The same report identifies 29 separate hotspot zones — clusters where modelled risk concentrates — against 8 for the Town of Paradise. Alta Sierra's risk is not funnelled into one or two obvious pinch points that a fuel break could address. It is distributed across the whole community, which is what a uniform fuel bed with houses embedded in it produces. And the drive-times to those hotspots run 13 to 15 minutes, roughly double the 5 to 10 minutes measured into Paradise's hotspots.

Excerpt from a Satelife neighborhood wildfire report for Alta Sierra: fire-service reach and community egress table showing a 4.1-minute fastest fire-truck drive-time from Nevada County Consolidated Fire Station 89, 17 stations within 15 km, 29 independent road exits, no bottleneck detected, and hotspot drive-times of 13.5 to 15.4 minutes — **Report excerpt** — Access & Evacuation, Satelife Neighborhood Wildfire Risk Report for Alta Sierra, CA (July 2026). Modelled OSRM drive-times from OSM-mapped stations; volunteer-staffed stations are frequently absent from OSM and would shorten local response. Decision support, not an evacuation plan or a guaranteed response time.

Fire behaviour

What the federal model says about four-foot flames

The cleanest way to see the difference between a burned county and an unburned one is the USFS Wildfire Risk to Communities layer, which models burn probability and conditional flame length from the actual fuel bed. At the Alta Sierra parcel it returns 49 / 100, and a 28.1% probability of flame lengths exceeding four feet in a fire event.

Four feet is the operational threshold at which direct attack by hand crews stops working and the fight becomes an equipment-and-air-support problem. A 28% chance of crossing it is the modelled fuel bed telling you what kind of fire this landscape is currently able to produce. For comparison, the same model at our Paradise case study returns 8 / 100 and a probability of 0.0% — because the fuel there burned in 2018 and has not grown back yet.

Set the two hazard framings side by side and the county's real position is clear:

90CAL FIRE hazard zone layer — Very High, unchanged

49USFS WRC fire-behaviour model (Paradise: 8)

28.1%modelled probability of flame lengths over 4 ft (Paradise: 0.0%)

20fire-history layer — one fire in twenty years

The layer that looks best on this page — a near-empty fire history — is the one doing the most to make the headline number look comfortable. It is also the one with the least to say about what happens next.

Case study

One address on Alta Sierra Drive, scored today

We ran a full Satelife wildfire-risk report for a property on Alta Sierra Drive, Grass Valley — inside the Very High zone, inside the canopy, with no significant fire in living memory. The composite: 48 / 100 — Moderate tier, at 0.84 confidence, from ten independently-scored layers.

Excerpt from a Satelife wildfire risk report for Alta Sierra Drive, Grass Valley: per-layer contributions showing Hazard 90, Vision 84, Terrain 65, Fire Weather 65, USFS WRC 49, Community preparedness 38, Vegetation 37, Fire history 20, Road access 10 and Fire-spread sim 5 — **Report excerpt** — Per-layer contributions, Satelife Wildfire Risk Report, Alta Sierra Drive, Grass Valley, CA 95949 (July 2026). Composite 48/100, Moderate tier.

What drives the score:

Hazard zone: 90/100. CAL FIRE Very High Fire Hazard Severity Zone.
AI vision analysis: 84/100 — Very High, and the second-highest layer. The model reads the parcel's own imagery and finds a semi-rural wooded setting with moderately continuous canopy across the parcel and adjoining land, mature trees near and partly over the structure and drive approach, and maintained space that stops short of the full defensible-space envelope. Two of the four street-view aspects are flagged for heavy fuels near the structure.
Fire weather: 65/100. Thirty-year ERA5 climatology of the Canadian Fire Weather Index — hotter and drier than the Butte County comparison.
Fire history: 20/100. One fire in twenty years, nine acres. The lowest layer in the report, and the reason the composite reads Moderate rather than High.

Excerpt from a Satelife wildfire risk report: fire history layer for Alta Sierra listing OAK 2018 at 9 acres, HALCON 2002 at 20 acres, NEWNAN LIGHTNING #9 1960 at 739 acres and RATTLESNAKE 1951 at 586 acres, with 1 fire in the last 20 years and a layer score of 20 out of 100 — **Report excerpt** — Fire history: four mapped NIFC perimeters in seventy-five years, one of them in the last twenty. The layer scores recurrence, and there is very little to score.

Two houses, ninety minutes apart, both scoring 48. In Paradise the number is held up by fire history and held down by an absent fuel bed. In Alta Sierra it is the exact reverse. The composite is identical; the correct next action is not.

The report pairs the score with a prioritized plan for this parcel: audit defensible space annually before fire season, and verify access-route width and gate clearance — the second one carrying more weight here than it would elsewhere, given roadside canopy along the subdivision's internal roads. Under the Safer from Wildfires rules, completing and documenting that work is insurance evidence, not just safety advice.

Insurance & real estate

Underwriting does not wait for a fire history

Carriers do not price Nevada County off its quiet perimeter record — they price it off hazard zone, fuel model and structure exposure, all three of which read badly here. This is not a hypothetical. When the California Department of Insurance ranked counties by the concentration of homes in high fire-risk exposure, Nevada County came third in the state, behind only Tuolumne and Trinity. Across that top-ten group, policy non-renewals rose from 6,372 in 2018 to 19,282 in 2019 — a 203% increase against 31% statewide — and Nevada County was one of six counties that wrote more new FAIR Plan policies in the first seven months of 2019 than in the whole of 2015–2018 combined.

That pressure has not eased. The California FAIR Plan, the insurer of last resort, reported 668,609 policies in force in December 2025 — a 146% increase since September 2022, against roughly $724 billion of exposure. FAIR Plan coverage is more expensive and thinner than what it replaces.

This is the specific trap for a Nevada County homeowner: the intuition that "we have never had a big fire here" is contradicted by the underwriting, and the composite risk score — pulled toward Moderate by the same quiet history — can appear to support the intuition. The per-layer breakdown is what resolves it, and it is also what an insurer's mitigation review is asking about. Under Safer from Wildfires (10 CCR § 2644.9), every admitted carrier that prices on wildfire risk must offer discounts for documented mitigation at the structure, defensible-space and community levels — which makes dated parcel evidence financially material rather than merely prudent.

For buyers and sellers, California Civil Code §1103 requires Natural Hazard Disclosure at the point of sale, and fire-zone status is increasingly a closing-risk variable rather than a paperwork item — a buyer who cannot bind insurance cannot close. See California wildfire insurance and California real estate wildfire risk.

Sources: California Department of Insurance · California FAIR Plan · 10 CCR § 2644.9 (Safer from Wildfires).

Risk reduction

What Nevada County homeowners can actually do

CAL FIRE's defensible-space framework defines three zones: Zone 0 (0–5 ft, ember-resistant, no combustibles), Zone 1 (5–30 ft, lean-clean-green), and Zone 2 (30–100 ft, reduced fuel). In a community where the canopy is continuous and parcels are large and wooded, Zone 2 work is where the effort goes — and it is the zone most often left undone, because it usually means removing trees people bought the property for. The Fire Safe Council of Nevada County coordinates chipping and community fuel-reduction programs that make that work affordable at the neighborhood scale, which is the scale at which the 29 hotspot zones above actually respond.

The comparison that makes the point is Butte County. Paradise and Alta Sierra return the same composite — 48 / 100 — and almost nothing else in common. Paradise: fire history 80, USFS WRC 8, four-foot flame probability 0.0%, hotspot drive-times 5 to 10 minutes, 8 hotspot zones. Alta Sierra: fire history 20, USFS WRC 49, four-foot flame probability 28.1%, hotspot drive-times 13 to 15 minutes, 29 hotspot zones. In Butte County the mitigation question is how to build back into a hazard that never changed. In Nevada County it is how to reduce a fuel load before it is tested for the first time in a generation.

Coverage

ZIP codes we cover in Nevada County

Satelife runs address-level wildfire reports across every ZIP code in Nevada County. The ZIPs below are the high Fire Hazard Severity Zone, Wildland-Urban Interface communities we are asked about most. One caveat that is the whole point of what we do: the risk score is computed for your parcel, not the ZIP, so two homes on the same street can land in different tiers. Find your area, then run your address.

ZIP code	Community	Why it is on the map
95949	Grass Valley (Alta Sierra)	Forested subdivision WUI; Alta Sierra Drive case study
95945	Grass Valley	City core with continuous canopy to the boundary
95959	Nevada City	Historic county seat inside mixed conifer
95946	Penn Valley	Lake Wildwood; inside the 1988 49er Fire footprint
95975	Rough and Ready	Oak woodland and grass WUI west of Grass Valley
95924	Cedar Ridge	Highway 174 forest corridor between Grass Valley and Colfax
95960	North San Juan	San Juan Ridge community above the Yuba canyons
96161	Truckee	East-county Sierra crest; a different fuel and snow regime

ZIP areas per USPS; Wildland-Urban Interface and Fire Hazard Severity Zone framing per CAL FIRE.

Where to go next

Nevada County wildfire risk in context

California wildfire risk The statewide picture: FHSZ, county exposure, 2026 season Butte County wildfire risk The burned counterpart: Camp Fire legacy, Paradise case study Placer County wildfire risk Mosquito Fire legacy, Foresthill Divide geography El Dorado County wildfire risk Caldor Fire legacy, Grizzly Flats case study California wildfire insurance FAIR Plan, non-renewals, Safer from Wildfires discounts California real estate wildfire risk Buyer due diligence and disclosure Create a wildfire evacuation plan Zones, egress routes, refuge areas Run a wildfire risk report PDF + score + mitigation plan

FAQ

Frequently asked questions about Nevada County wildfire risk

Is Nevada County a high wildfire risk area?

Yes, and for a reason that does not show up in a fire-history search. The populated western county — Grass Valley, Nevada City, Alta Sierra, Penn Valley, Cedar Ridge — sits in CAL FIRE High and Very High Fire Hazard Severity Zones under a largely intact fuel bed. A Satelife hazard layer for an Alta Sierra address reads 90/100, and the USFS Wildfire Risk to Communities model puts the probability of flame lengths over four feet at 28.1% there.

When did Nevada County last have a major wildfire?

The county’s benchmark event is the 1988 49er Fire, west of Grass Valley. Since then the record near Grass Valley has been unusually quiet: the Satelife fire-history layer for an Alta Sierra parcel finds only four mapped NIFC perimeters in total and just one in the last twenty years — the 2018 Oak Fire, at nine acres. That quiet record is exactly why the fuel is still standing.

Why does my Nevada County score look moderate when the hazard zone is Very High?

Because the composite blends ten layers and the fire-history layer is scored on recurrence. Around Alta Sierra it reads 20/100 — one fire in twenty years. That pulls the headline number down while the hazard layer sits at 90/100, fire weather at 65/100 and the federal fire-behaviour model at 49/100. The composite is a summary, not a verdict; the per-layer breakdown is where the decision lives.

How do I check the fire hazard zone for my Grass Valley or Nevada City address?

Use the CAL FIRE FHSZ viewer for the official Moderate / High / Very High classification. For property-level detail — terrain, fuels, fire history, evacuation constraints, and an AI read of your actual parcel imagery — run a Satelife address-level report.

Can wildfire mitigation lower my insurance premium in Nevada County?

Yes. California’s Safer from Wildfires regulation (10 CCR § 2644.9, effective October 2022) requires every admitted insurer that prices on wildfire risk to offer discounts for twelve specific mitigation measures — covering the structure, the defensible-space zone around it, and community-level designations such as Firewise USA. Documented defensible space and home hardening, of the kind a Satelife report captures and dates, is the evidence that pathway runs on.

Wildfire risk in Nevada County: the fuel that hasn't burned yet