Trinity County, California Natural Disaster Risk
FEMA National Risk Index assessment · CA
LowComposite Risk Score
National percentile: 79th
Trinity County faces low composite natural disaster risk (NRI Risk Index score 79.5, 79th national percentile), driven primarily by landslide and wildfire exposure. Expected annual loss across all 18 hazard types is $29M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Trinity County carries a low composite natural disaster risk, with a National Risk Index score of 79.5 out of 100 — placing it in the 79th national percentile and below the national average for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
The county's risk is driven primarily by landslide (downhill movement of rock, soil, and debris on unstable slopes) at High risk — $730K in expected annual loss and about 18.46 events per year; wildfire (uncontrolled fires that spread across wildland and into communities) at High risk — $13M in expected annual loss and about 0.03 events per year; and earthquake (ground shaking from sudden movement along geologic faults) at Low risk — $2M in expected annual loss and about 0.03 events per year. Across all hazards, FEMA estimates $29M in expected annual loss for a population of 16K.
Beyond physical exposure, Trinity County has a very high social vulnerability rating (how susceptible the population is to harm) and a low community resilience rating (its capacity to prepare for and recover from disasters). That combination — a more vulnerable population with limited resilience — can amplify the human cost of any given event.
The federal record bears this out: Trinity County has received 32 federal disaster declarations since 1964, including 9 for severe storm events and 9 for flood 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, Trinity County ranks #50 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Landslide | High | 18.46 / yr | $730K |
| Wildfire | High | 0.03 / yr | $13M |
| Earthquake | Low | 0.03 / yr | $2M |
| Riverine Flood | Medium | 0.21 / yr | $13M |
| Volcanic Activity | Very Low | 0.00 / yr | $14 |
| Avalanche | Very Low | 0.01 / yr | $630 |
| Heat Wave | Low | 4.85 / yr | $161K |
| Lightning | Very Low | 9.65 / yr | $27K |
| Winter Weather | Very Low | 24.15 / yr | $4K |
| Hail | Very Low | 0.09 / yr | $9K |
| Tornado | Very Low | 0.03 / yr | $11K |
| Strong Wind | Very Low | 0.01 / yr | $4K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Cold Wave | Very Low | 0.00 / yr | $0 |
| Drought | Very Low | 58.49 / 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
Trinity County has received 32 federal disaster declarations since 1964, most recently Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides in April 2023. Most frequent causes: Severe Storm (9), Flood (9), Fire (9).
| 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 2021 | Fire | Wildfires |
| August 2021 | Fire | Monument Fire |
| 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 |
| May 2019 | Severe Storm | Severe Winter Storms, Flooding, Landslides, and Mudslides |
Showing the 10 most recent of 32 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Trinity County?
Trinity County has a composite FEMA National Risk Index score of 79.5 out of 100, placing it in the Low category and the 79th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Trinity County?
The three highest-rated hazards are Landslide (High, $730K EAL), Wildfire (High, $13M EAL), Earthquake (Low, $2M EAL). These account for most of the county's expected annual losses.
How does Trinity County compare to other California counties?
Trinity County ranks #50 of 58 California counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Trinity County had?
FEMA records 32 federal disaster declarations for Trinity County since 1964, most often 9 for severe storm events and 9 for flood 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. Trinity County's $29M EAL is a statistical average, not a guarantee for any specific year or address.