Johnson County, Wyoming Natural Disaster Risk
FEMA National Risk Index assessment · WY
Very LowComposite Risk Score
National percentile: 19th
Johnson County faces very low composite natural disaster risk (NRI Risk Index score 19.3, 19th national percentile), driven primarily by wildfire and landslide exposure. Expected annual loss across all 18 hazard types is $7M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Johnson County carries a very low composite natural disaster risk, with a National Risk Index score of 19.3 out of 100 — placing it in the 19th 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.
The county's risk is driven primarily by wildfire (uncontrolled fires that spread across wildland and into communities) at Low risk — $958K in expected annual loss and about 0.00 events per year; landslide (downhill movement of rock, soil, and debris on unstable slopes) at Low risk — $8K in expected annual loss and about 7.93 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at Medium risk — $110K in expected annual loss and about 16.70 events per year. Across all hazards, FEMA estimates $7M in expected annual loss for a population of 8K.
Beyond physical exposure, Johnson County has a medium social vulnerability rating (how susceptible the population is to harm) and a very 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.
History supports the rating: Johnson County has received 7 federal disaster declarations since 1978, including 2 for fire events and 2 for biological events. The most recent was Wildfires (fire), declared in November 2024.
Among 23 Wyoming counties, Johnson County ranks #18 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Wildfire | Low | 0.00 / yr | $958K |
| Landslide | Low | 7.93 / yr | $8K |
| Winter Weather | Medium | 16.70 / yr | $110K |
| Earthquake | Very Low | 0.00 / yr | $387K |
| Hail | Low | 1.08 / yr | $217K |
| Cold Wave | Low | 1.63 / yr | $616K |
| Riverine Flood | Low | 0.86 / yr | $4M |
| Avalanche | Very Low | 0.01 / yr | $68 |
| Lightning | Low | 37.24 / yr | $85K |
| Drought | Very Low | 104.48 / yr | $4K |
| Tornado | Very Low | 0.49 / yr | $145K |
| Strong Wind | Very Low | 0.61 / yr | $116K |
| Heat Wave | Very Low | 0.23 / yr | $9K |
| Ice Storm | Very Low | 0.01 / yr | $3K |
| Coastal Flood | 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
Johnson County has received 7 federal disaster declarations since 1978, most recently Wildfires in November 2024. Most frequent causes: Fire (2), Biological (2), Flood (2).
| Declared | Type | Disaster |
|---|---|---|
| November 2024 | Fire | Wildfires |
| August 2024 | Fire | House Draw Fire |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| July 2015 | Flood | Severe Storms and Flooding |
| July 2011 | Severe Storm | Severe Storms, Flooding, and Landslides |
| May 1978 | Flood | Severe Storms, Flooding & Mudslides |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Johnson County?
Johnson County has a composite FEMA National Risk Index score of 19.3 out of 100, placing it in the Very Low category and the 19th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Johnson County?
The three highest-rated hazards are Wildfire (Low, $958K EAL), Landslide (Low, $8K EAL), Winter Weather (Medium, $110K EAL). These account for most of the county's expected annual losses.
How does Johnson County compare to other Wyoming counties?
Johnson County ranks #18 of 23 Wyoming counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Johnson County had?
FEMA records 7 federal disaster declarations for Johnson County since 1978, most often 2 for fire events and 2 for biological events. The most recent was Wildfires, declared in November 2024.
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. Johnson County's $7M EAL is a statistical average, not a guarantee for any specific year or address.