Tuolumne County, California Natural Disaster Risk
FEMA National Risk Index assessment · CA
MediumComposite Risk Score
National percentile: 85th
Tuolumne County faces medium composite natural disaster risk (NRI Risk Index score 85.2, 85th national percentile), driven primarily by wildfire and landslide exposure. Expected annual loss across all 18 hazard types is $51M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Tuolumne County at medium composite risk, with a National Risk Index score of 85.2 out of 100 — placing it in the 85th national percentile and near the national midpoint for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Tuolumne County's expected losses come from wildfire (uncontrolled fires that spread across wildland and into communities) at High risk — $27M in expected annual loss and about 0.01 events per year; landslide (downhill movement of rock, soil, and debris on unstable slopes) at Medium risk — $59K in expected annual loss and about 4.42 events per year; and heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at Medium risk — $3M in expected annual loss and about 3.35 events per year. Across all hazards, FEMA estimates $51M in expected annual loss for a population of 56K.
Beyond physical exposure, Tuolumne County has a medium social vulnerability rating (how susceptible the population is to harm) and a medium community resilience rating (its capacity to prepare for and recover from disasters). Both measures sit toward the lower end, indicating relatively modest population sensitivity.
The federal record bears this out: Tuolumne County has received 21 federal disaster declarations since 1964, including 7 for flood events and 6 for severe storm events. The most recent was Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides (severe storm), declared in April 2023.
Among 58 California counties, Tuolumne County ranks #46 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Wildfire | High | 0.01 / yr | $27M |
| Landslide | Medium | 4.42 / yr | $59K |
| Heat Wave | Medium | 3.35 / yr | $3M |
| Riverine Flood | Medium | 0.96 / yr | $19M |
| Drought | Medium | 90.68 / yr | $595K |
| Lightning | Medium | 20.27 / yr | $501K |
| Earthquake | Low | 0.02 / yr | $769K |
| Winter Weather | Medium | 33.02 / yr | $95K |
| Volcanic Activity | Very Low | 0.00 / yr | $39 |
| Avalanche | Very Low | 0.03 / yr | $1K |
| Strong Wind | Very Low | 0.05 / yr | $104K |
| Hail | Very Low | 0.11 / yr | $29K |
| Tornado | Very Low | 0.13 / yr | $38K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Cold Wave | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Ice Storm | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Disaster History
Tuolumne County has received 21 federal disaster declarations since 1964, most recently Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides in April 2023. Most frequent causes: Flood (7), Severe Storm (6), Fire (4).
| Declared | Type | Disaster |
|---|---|---|
| April 2023 | Severe Storm | Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides |
| March 2023 | Flood | Severe Winter Storms, Flooding, Landslides, and Mudslides |
| January 2023 | Flood | Severe Winter Storms, Flooding, Landslides, and Mudslides |
| August 2020 | Fire | Wildfires |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| May 2019 | Severe Storm | Severe Winter Storms, Flooding, Landslides, and Mudslides |
| April 2017 | Flood | Severe Winter Storms, Flooding, and Mudslides |
| March 2017 | Flood | Severe Winter Storms, Flooding, and Mudslides |
| February 2017 | Severe Storm | Severe Winter Storms, Flooding, and Mudslides |
Showing the 10 most recent of 21 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Tuolumne County?
Tuolumne County has a composite FEMA National Risk Index score of 85.2 out of 100, placing it in the Medium category and the 85th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Tuolumne County?
The three highest-rated hazards are Wildfire (High, $27M EAL), Landslide (Medium, $59K EAL), Heat Wave (Medium, $3M EAL). These account for most of the county's expected annual losses.
How does Tuolumne County compare to other California counties?
Tuolumne County ranks #46 of 58 California counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Tuolumne County had?
FEMA records 21 federal disaster declarations for Tuolumne County since 1964, most often 7 for flood events and 6 for severe storm events. The most recent was Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared in April 2023.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Tuolumne County's $51M EAL is a statistical average, not a guarantee for any specific year or address.