Wildfire risk in Tuolumne County: where it is highest, and why
Wildfire risk in Tuolumne County varies a lot by location. In the places we scored, overall scores run from 37.1 in unincorporated Tuolumne County to 83.6 near Groveland, with a middle value of 68.1.
Tuolumne County — the largest fires on record, at their perimeter centres, with the county’s main communities. Select a marker for its detail.
At a glance
Half of Tuolumne County scores High or worse
We scored 156 points across Tuolumne County on the same 0–100 scale a Satelife address report uses, and they do not land in one place. 20% of them come out Very High, while 10% are Moderate. Which end your own parcel sits at is not something a county map can tell you.
20%
71%
Very High20% · 31 of 156 pointsHigh71% · 110 of 156 pointsModerate10% · 15 of 156 points
Safest end we measured37.1near unincorporated Tuolumne County · Moderate
Middle of the county68.1High — half of Tuolumne County is above this
Most exposed end we measured83.6near Groveland · Very High
And the federal models agree it is a fire county
Relatively HighFEMA National Risk Index — wildfire risk rating · index score 99.3 / 100
$27.3M / yrFEMA NRI — expected annual loss from wildfire · rated Relatively High
1.01%USFS Wildfire Risk to Communities — mean annual burn probability · 90th-percentile cell 2.81%
6.21 ftUSFS WRC — mean conditional flame length · 97% of the county carries burnable fuel
FEMA NRI also rates Tuolumne County: all-hazards risk Relatively Moderate · social vulnerability Relatively Moderate · community resilience Relatively Moderate · annualised wildfire frequency 0.0124.
Sources: FEMA National Risk Index 1.20.0 (Dec 2025), county record · USFS Wildfire Risk to Communities v2.0, mean of the grid cells inside the county. Both describe the county as a whole, never an address in it.
What does your Tuolumne County address score?
A county range shows the spread. Your parcel sits somewhere inside it — the report says where, and what to do about it.
Free to request · PDF report with a 0–100 score, the drivers behind it, and a mitigation plan
Local context
What the data says about Tuolumne County
Most scored locations fall in the High tier: 110 points were High, compared with 31 in Very High and 15 in Moderate. No scored points fell in the Low tier.
For county-wide context, FEMA’s National Risk Index rates Tuolumne County’s wildfire risk as Relatively High, and its wildfire expected annual loss as Relatively High.
Fire record
Where the fires actually were
The largest fire listed here is the Rim fire (2013), at 256,916 acres.
The most recent large fire listed here is the 6-5 fire (2025), at 6,935 acres.
Since 1984, 670,897 acres have burned in the county, which is 46.3% of the county.
The Hamm fire (1987) is marked as partly in Tuolumne County.
Rim Fire, 2013 — Tuolumne County.
Photo: Spc. Nadine White · Public domainDonnell Fire, 2018 — Tuolumne County.
Photo: Forest Service Photography · Public domain
492mapped fire perimeters centred in the county since 1984
670,897acres inside those perimeters since 1984
46.3%of the county's area, as a share of 5,867.5 km²
6-5 2025most recent large fire on record
Before 20002000s2010s2020s
Fire perimeters coloured by decade. Select a perimeter for its name, year and size.
Named fires on record
Rim Fire2013256,916 acres
Donnell Fire201836,461 acres
Ackerson Fire199659,151 acres
Paper Fire198745,020 acres
Hamm Fire198733,144 acres in totalcrossed into the county
Quarry Fire20238,645 acres
Rogge Fire199620,944 acres
6-5 Fire20256,935 acres
Perimeter sources: NIFC Interagency Fire Perimeter History · WFIGS Interagency Perimeters · largest on record: Rim 2013.
Perimeters are simplified for display; acreage is the figure the source records.
Communities
Where in the county you are matters most
Among named communities, Groveland has one of the higher typical scores at 76.9. Sonora is 72.7, and Tuolumne is 71.2.
Columbia scores 69.3 and Twain Harte 66.4, while Jamestown is lower at 62.7.
Compared with the county middle score of 68.1, several communities sit above that level and several sit below it, which matches the street-to-street variation seen across the county.
Grovelandvillage · 601 people
76.9 Very High
Sonoratown · 4,648 people
72.7 High
Tuolumnevillage
71.2 High
Columbiavillage
69.3 High
Twain Hartevillage
66.4 High
Jamestownvillage · 3,433 people
62.7 High
The score is the median of the sampled points nearest that community — a community-scale
indicator, not a score for any individual property in it. Population comes from the
community's own record where the source carries one.
Terrain & fuels
Terrain, vegetation and fuels
Terrain contributes to higher wildfire risk in parts of Tuolumne County. Terrain scores range from 20.0 near Jamestown to 65.0 in Groveland, with a middle value of 55.0.
Vegetation and fuels are also elevated in many places: scores run from 20.0 in Twain Harte to 80.0 near Groveland, with a middle value of 74.0.
Fire weather was not measured at all for this county in the places we scored. What we do have countywide scoring for includes hazard-zone and fire-history factors, which have middle values of 73.2 and 70.0.
55median terrain score (max 65 near Groveland)
74median vegetation & fuels score (max 80 near Groveland)
LANDFIRE existing vegetation type across Tuolumne County — the same fuel data that feeds the
vegetation layer of a Satelife property report.
Fire weather
Fire weather across Tuolumne County
Fire weather was not measured at the sampled points in Tuolumne County. The other four
indicators on this page were, and the bars below show what they found.
What drives it
Which part of the risk moves, and which doesn't
Risk is not even across the county. The lowest scored location is 37.1 in unincorporated Tuolumne County, while the highest is 83.6 near Groveland.
That spread sits around a middle score of 68.1, so many neighborhoods are in a higher-risk band even though some spots score much lower.
By tier count, High is the most common group with 110 scored points, followed by Very High with 31 and Moderate with 15.
Each bar is what one part of the score covers across Tuolumne County, on the same 0–100 scale.
A long bar is a part of the risk that depends on where you are; a short one is the same
almost everywhere.
Terrain
20–65highest near Groveland
Vegetation & fuels
20–80highest near Groveland
Hazard zone
10–94.5highest near Twain Harte
Fire history
5–95highest near Jamestown
Overall score
37.1–83.6highest near Groveland
The tick on each bar is the middle value. Tier boundaries — Moderate at 25, High at 50,
Very High at 75 — are the faint lines behind them.
Show every number behind these bars
Layer
Min
Median
Max
Lowest place
Highest place
Points
Terrain
20
55
65
near Jamestown
Groveland
156
Vegetation & fuels
20
74
80
Twain Harte
near Groveland
156
Hazard zone
10
73.2
94.5
unincorporated Tuolumne County
Twain Harte
156
Fire history
5
70
95
unincorporated Tuolumne County
near Jamestown
156
Composite
37.1
68.1
83.6
unincorporated Tuolumne County
near Groveland
156
Independently of Satelife's layers, the USFS Wildfire Risk to Communities grid puts the county's mean annual burn probability at 1.01% (90th percentile cell: 2.81%), with a mean conditional flame length of 6.21 ft. 97% of the 20,767 grid cells inside the county carry burnable fuel at all.
Source: USFS Wildfire Risk to Communities v2.0 (ImageServer, county extent).
CAL FIRE has no mapped Fire Hazard Severity Zone at 114 of the 156 sampled points — the zones cover Local Responsibility Areas, and most of this county is state or federal land. At 113 of them the USFS grid above supplied the hazard reading instead; at the remaining 1 the hazard weight is renormalised away rather than scored as low.
156 sample points on a ~2.3 km grid, plus one at the centre of each community, weighted with the Satelife county profile v1 · median layer coverage 90%. Scores are 0–100 and comparable within the county, not across states.
For a property
What a county range means for one address
Hazard-zone scores are high in many places we scored. The highest is 94.5 in Twain Harte, the middle is 73.2, and the low end is 10.0 in unincorporated Tuolumne County.
Fire-history scores also span a wide range: up to 95.0 near Jamestown, with a middle value of 70.0 and a low of 5.0 in unincorporated Tuolumne County.
In the USFS Wildfire Risk to Communities product, mean annual burn probability is 1.01%, and the 90th-percentile cell burn probability is 2.81%.
That same USFS product indicates 97.4% of the county can burn, and lists a mean conditional flame length of 6.21 feet.
Across 156 sampled points in Tuolumne County, the score runs from
37.1 to 83.6 — two neighbouring parcels can sit in different tiers.
A county number is the middle of that spread; it says nothing about which end yours is at.
Find out where your Tuolumne County parcel sits
Slope, the fuel touching the structure, the road out, the fire history within a mile — measured at your address, not averaged across the county.
Free to request · PDF report with a 0–100 score, the drivers behind it, and a mitigation plan
Coverage
ZIP codes we cover in Tuolumne County
Every one of the 27 ZIP areas that touch Tuolumne County — we run address-level
reports in all of them. They are grouped by the median score of the points we sampled inside
each, which is a neighbourhood-scale indicator and not a score for any
property: two homes in the same ZIP routinely land in different tiers.
Frequently asked questions about Tuolumne County wildfire risk
What risk tier is most common in Tuolumne County?
High is the most common tier in the scored locations, with 110 points. Very High has 31 points, and Moderate has 15.
What are the largest and most recent large fires listed for this county?
The largest listed fire is Rim (2013). The most recent large fire listed is 6-5 (2025).
Is fire weather included in these county scores?
No. Fire weather was not measured at all for this county in the places we scored. The page does include other wildfire-risk factors such as terrain, vegetation and fuels, hazard-zone, and fire-history scores.
What does FEMA say about county-wide wildfire risk?
FEMA’s National Risk Index rates Tuolumne County’s wildfire risk as Relatively High, and its wildfire expected annual loss as Relatively High.
How much of Tuolumne County has burned since 1984?
46.3% of the county has burned since 1984, totaling 670,897 acres.
This page is generated from a Tuolumne County data pack assembled on 2026-08-18 (pack v1.0). Scores are sampled across the
county, not measured at any individual address, and are informational decision support — not a
substitute for official evacuation orders, a fire-agency hazard determination, or an insurer's
underwriting judgement.
Data versions: fema_nri 1.20.0 (Dec 2025) · landfire per adapter · nifc_history All Years View · wfigs current · wrc v2.0 (2024) · zcta Census 2020.
What does your parcel look like, layer by layer?
A county range shows the spread. An address-level Satelife report shows where in that spread your property actually sits — PDF, per-layer score, and a prioritized mitigation plan.
