Wildfire risk in Tuolumne County: where it is highest, and why
Wildfire risk is elevated in many parts of Tuolumne County. Across the places we scored, the overall risk runs from 38.8 up to 80.8, with a county midpoint of 66.8.
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. 12% of them come out Very High, while 9% are Moderate. Which end your own parcel sits at is not something a county map can tell you.
12%
79%
Very High12% · 19 of 156 pointsHigh79% · 123 of 156 pointsModerate9% · 14 of 156 points
Safest end we measured38.8near unincorporated Tuolumne County · Moderate
Middle of the county66.8High — half of Tuolumne County is above this
Most exposed end we measured80.8near 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
FEMA’s National Risk Index rates Tuolumne County’s wildfire risk as “Relatively High,” and its wildfire expected annual loss rating is also “Relatively High.” FEMA rates the county’s all-hazards risk as “Relatively Moderate.”
Since 1984, 46.3% of the county has burned, totaling 670,897 acres. That burn footprint is a major part of the county’s wildfire-risk picture.
Fire record
Where the fires actually were
The largest fire in this record is the Rim fire (2013), at 256,916 acres.
The most recent large fire is the 6-5 fire (2025), at 6,935 acres.
Other major fires in and around the county include the Donnell fire (2018) at 36,461 acres and the Ackerson fire (1996) at 59,151 acres. The Hamm fire (1987), at 33,144 acres, was partly in Tuolumne County.
Since 1984, there have been 492 fire perimeters in the county, and 670,897 acres have burned in total.
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 the named communities, Groveland has the highest midpoint score at 74.6. Sonora is 70.9, and Jamestown is 61.9.
Tuolumne is 69.5, Columbia is 67.8, and Twain Harte is 65.2.
These community values describe the places we scored around each community, not a guarantee about any single parcel.
Grovelandvillage · 601 people
74.6 High
Sonoratown · 4,648 people
70.9 High
Tuolumnevillage
69.5 High
Columbiavillage
67.8 High
Twain Hartevillage
65.2 High
Jamestownvillage · 3,433 people
61.9 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 meaningfully to differences across the county. Terrain scores run from 20.0 near Jamestown to 65.0 in Groveland, with a midpoint 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 midpoint of 74.0.
Hazard-zone scores are high in several communities, reaching 94.5 in Twain Harte, with a county midpoint of 73.2 and a low of 10.0 in unincorporated Tuolumne County.
Fire-history scores range from 5.0 in unincorporated Tuolumne County to 95.0 near Jamestown, with a midpoint of 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 scores are measured across the county, and they vary less than some other factors. They run from 54.2 to 62.2, with a midpoint of 55.0.
Compared with terrain, fuels, and fire history, this narrower spread means place-to-place differences in wildfire risk are more strongly associated with non-weather factors in this county scoring.
54.2lowest fire-weather score — near unincorporated Tuolumne County
62.2highest fire-weather score — near unincorporated Tuolumne County
What drives it
Which part of the risk moves, and which doesn't
Risk is not uniform inside Tuolumne County. The highest scored location is near Groveland at 80.8, while the lowest scored location is in unincorporated Tuolumne County at 38.8.
Most scored points fall in the High tier, with 123 locations.
Very High appears at 19 locations, Moderate at 14, and Low at 0. So the county’s scored locations are concentrated in High and Very High tiers.
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
Fire weather
54.2–62.2highest near unincorporated Tuolumne County
Overall score
38.8–80.8highest 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
Fire weather
54.2
55
62.2
unincorporated Tuolumne County
unincorporated Tuolumne County
156
Composite
38.8
66.8
80.8
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 100%. Scores are 0–100 and comparable within the county, not across states.
For a property
What a county range means for one address
For property-level context, the USFS Wildfire Risk to Communities model reports a mean annual burn probability of 1.01% for the county, with higher-end mapped cells at 2.81%.
That same model indicates 97.4% of the county can burn, and reports mean conditional flame length of 6.21 feet.
This USFS product is a modeled burn-probability view of wildfire risk, not a fire-weather score. For county-wide context, FEMA’s National Risk Index rates Tuolumne County’s wildfire risk as “Relatively High.”
Across 156 sampled points in Tuolumne County, the score runs from
38.8 to 80.8 — 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 does the county’s risk pattern look like at a glance?
Most scored locations are in the High tier (123 points), with another 19 in Very High and none in Low. The overall county scoring midpoint is 66.8.
Which fire was the largest, and which one is the most recent large fire?
The largest is the Rim fire (2013) at 256,916 acres. The most recent large fire is the 6-5 fire (2025) at 6,935 acres.
Is wildfire risk the same in every community?
No. In the listed communities, Groveland is higher at 74.6, while Jamestown is lower at 61.9. Sonora is 70.9.
How much of Tuolumne County has burned since 1984?
46.3% of the county has burned since 1984, totaling 670,897 acres.
How does FEMA rate wildfire risk for the county?
FEMA’s National Risk Index rates Tuolumne County’s wildfire risk as “Relatively High,” and its wildfire expected annual loss rating is also “Relatively High.”
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.
