Big Horn County, Montana Natural Disaster Risk
FEMA National Risk Index assessment · MT
LowComposite Risk Score
National percentile: 57th
Big Horn County faces low composite natural disaster risk (NRI Risk Index score 57.2, 57th national percentile), driven primarily by strong wind and wildfire exposure. Expected annual loss across all 18 hazard types is $11M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Big Horn County carries a low composite natural disaster risk, with a National Risk Index score of 57.2 out of 100 — placing it in the 57th 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.
Most of Big Horn County's expected losses come from strong wind (damaging straight-line winds outside of tornadoes and hurricanes) at High risk — $2M in expected annual loss and about 0.83 events per year; wildfire (uncontrolled fires that spread across wildland and into communities) at Medium risk — $2M in expected annual loss and about 0.01 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at High risk — $212K in expected annual loss and about 24.45 events per year. Across all hazards, FEMA estimates $11M in expected annual loss for a population of 13K.
Beyond physical exposure, Big Horn County has a very high 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). That combination — a more vulnerable population with limited resilience — can amplify the human cost of any given event.
The federal record bears this out: Big Horn County has received 9 federal disaster declarations since 1978, including 2 for fire events and 2 for biological events. The most recent was Severe Winter Storm and Straight-Line Winds (straight-line winds), declared in April 2026.
Among 56 Montana counties, Big Horn County ranks #13 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Strong Wind | High | 0.83 / yr | $2M |
| Wildfire | Medium | 0.01 / yr | $2M |
| Winter Weather | High | 24.45 / yr | $212K |
| Lightning | High | 32.42 / yr | $493K |
| Cold Wave | Medium | 3.15 / yr | $2M |
| Landslide | Low | 5.18 / yr | $5K |
| Riverine Flood | Low | 0.68 / yr | $4M |
| Hail | Low | 1.58 / yr | $164K |
| Earthquake | Very Low | 0.00 / yr | $86K |
| Drought | Low | 74.59 / yr | $34K |
| Avalanche | Very Low | 0.01 / yr | $101 |
| Heat Wave | Very Low | 2.02 / yr | $103K |
| Ice Storm | Very Low | 0.01 / yr | $4K |
| Tornado | Very Low | 0.32 / yr | $54K |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Disaster History
Big Horn County has received 9 federal disaster declarations since 1978, most recently Severe Winter Storm and Straight-Line Winds in April 2026. Most frequent causes: Fire (2), Biological (2), Severe Storm (2).
| Declared | Type | Disaster |
|---|---|---|
| April 2026 | Straight-Line Winds | Severe Winter Storm and Straight-Line Winds |
| July 2021 | Fire | Pf Fire |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| June 2011 | Severe Storm | Severe Storms and Flooding |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| May 2001 | Severe Storm | Severe Winter Storms |
| August 2000 | Fire | Wildfires |
| May 1978 | Flood | Severe Storms & Flooding |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Big Horn County?
Big Horn County has a composite FEMA National Risk Index score of 57.2 out of 100, placing it in the Low category and the 57th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Big Horn County?
The three highest-rated hazards are Strong Wind (High, $2M EAL), Wildfire (Medium, $2M EAL), Winter Weather (High, $212K EAL). These account for most of the county's expected annual losses.
How does Big Horn County compare to other Montana counties?
Big Horn County ranks #13 of 56 Montana counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Big Horn County had?
FEMA records 9 federal disaster declarations for Big Horn County since 1978, most often 2 for fire events and 2 for biological events. The most recent was Severe Winter Storm and Straight-Line Winds, declared in April 2026.
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. Big Horn County's $11M EAL is a statistical average, not a guarantee for any specific year or address.