Carbon County, Wyoming Natural Disaster Risk
FEMA National Risk Index assessment · WY
Very LowComposite Risk Score
National percentile: 43th
Carbon County faces very low composite natural disaster risk (NRI Risk Index score 42.7, 43th national percentile), driven primarily by avalanche and lightning exposure. Expected annual loss across all 18 hazard types is $12M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Carbon County carries a very low composite natural disaster risk, with a National Risk Index score of 42.7 out of 100 — placing it in the 43rd national percentile and among the lowest-risk counties in the country. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Carbon County's expected losses come from avalanche (fast-moving snow and debris sliding down steep mountain slopes) at High risk — $2M in expected annual loss and about 0.13 events per year; lightning (electrical discharges from storms that ignite fires and cause casualties) at High risk — $1M in expected annual loss and about 44.16 events per year; and landslide (downhill movement of rock, soil, and debris on unstable slopes) at Medium risk — $51K in expected annual loss and about 3.31 events per year. Across all hazards, FEMA estimates $12M in expected annual loss for a population of 14K.
Beyond physical exposure, Carbon County has a medium 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). Both measures sit toward the lower end, indicating relatively modest population sensitivity.
The federal record bears this out: Carbon County has received 5 federal disaster declarations since 2011, including 2 for fire events and 2 for biological events. The most recent was Mullen Fire (fire), declared in September 2020.
Among 23 Wyoming counties, Carbon County ranks #10 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Avalanche | High | 0.13 / yr | $2M |
| Lightning | High | 44.16 / yr | $1M |
| Landslide | Medium | 3.31 / yr | $51K |
| Wildfire | Low | 0.00 / yr | $457K |
| Winter Weather | Medium | 24.50 / yr | $130K |
| Cold Wave | Medium | 3.61 / yr | $2M |
| Earthquake | Low | 0.00 / yr | $430K |
| Ice Storm | Low | 0.02 / yr | $90K |
| Riverine Flood | Low | 0.29 / yr | $6M |
| Drought | Very Low | 86.51 / yr | $4K |
| Strong Wind | Very Low | 0.23 / yr | $63K |
| Tornado | Very Low | 0.37 / yr | $47K |
| Hail | Very Low | 0.23 / yr | $11K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Heat Wave | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Carbon County has received 5 federal disaster declarations since 2011, most recently Mullen Fire in September 2020. Most frequent causes: Fire (2), Biological (2), Severe Storm (1).
| Declared | Type | Disaster |
|---|---|---|
| September 2020 | Fire | Mullen Fire |
| September 2020 | Fire | 316 Fire |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| July 2011 | Severe Storm | Severe Storms, Flooding, and Landslides |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Carbon County?
Carbon County has a composite FEMA National Risk Index score of 42.7 out of 100, placing it in the Very Low category and the 43th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Carbon County?
The three highest-rated hazards are Avalanche (High, $2M EAL), Lightning (High, $1M EAL), Landslide (Medium, $51K EAL). These account for most of the county's expected annual losses.
How does Carbon County compare to other Wyoming counties?
Carbon County ranks #10 of 23 Wyoming counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Carbon County had?
FEMA records 5 federal disaster declarations for Carbon County since 2011, most often 2 for fire events and 2 for biological events. The most recent was Mullen Fire, declared in September 2020.
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. Carbon County's $12M EAL is a statistical average, not a guarantee for any specific year or address.