Clark County, Idaho Natural Disaster Risk
FEMA National Risk Index assessment · ID
Very LowComposite Risk Score
National percentile: 1th
Clark County faces very low composite natural disaster risk (NRI Risk Index score 0.8, 1th national percentile), driven primarily by avalanche and wildfire exposure. Expected annual loss across all 18 hazard types is $1M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Clark County at very low composite risk, with a National Risk Index score of 0.8 out of 100 — placing it in the 1st 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 Clark County's expected losses come from avalanche (fast-moving snow and debris sliding down steep mountain slopes) at Medium risk — $468K in expected annual loss and about 0.07 events per year; wildfire (uncontrolled fires that spread across wildland and into communities) at Low risk — $151K in expected annual loss and about 0.00 events per year; and landslide (downhill movement of rock, soil, and debris on unstable slopes) at Very Low risk — $2K in expected annual loss and about 0.71 events per year. Across all hazards, FEMA estimates $1M in expected annual loss for a population of 783.
Beyond physical exposure, Clark County has a very low 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.
The county's disaster history tells the same story: Clark County has received 4 federal disaster declarations since 2005, including 2 for biological events and 1 for fire events. The most recent was Covid-19 Pandemic (biological), declared in April 2020.
Among 44 Idaho counties, Clark County ranks #44 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Avalanche | Medium | 0.07 / yr | $468K |
| Wildfire | Low | 0.00 / yr | $151K |
| Landslide | Very Low | 0.71 / yr | $2K |
| Earthquake | Very Low | 0.02 / yr | $109K |
| Volcanic Activity | Very Low | 0.00 / yr | $1 |
| Drought | Very Low | 92.83 / yr | $1K |
| Winter Weather | Very Low | 26.60 / yr | $15K |
| Cold Wave | Very Low | 2.58 / yr | $154K |
| Heat Wave | Very Low | 0.35 / yr | $7K |
| Lightning | Very Low | 35.87 / yr | $14K |
| Riverine Flood | Very Low | 0.29 / yr | $506K |
| Strong Wind | Very Low | 0.62 / yr | $10K |
| Hail | Very Low | 0.22 / yr | $3K |
| Tornado | Very Low | 0.13 / yr | $2K |
| Ice Storm | Very Low | 0.01 / yr | $336 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Disaster History
Clark County has received 4 federal disaster declarations since 2005, most recently Covid-19 Pandemic in April 2020. Most frequent causes: Biological (2), Fire (1), Hurricane (1).
| Declared | Type | Disaster |
|---|---|---|
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| July 2018 | Fire | Grassy Ridge Fire |
| September 2005 | Hurricane | Hurricane Katrina |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Clark County?
Clark County has a composite FEMA National Risk Index score of 0.8 out of 100, placing it in the Very Low category and the 1th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Clark County?
The three highest-rated hazards are Avalanche (Medium, $468K EAL), Wildfire (Low, $151K EAL), Landslide (Very Low, $2K EAL). These account for most of the county's expected annual losses.
How does Clark County compare to other Idaho counties?
Clark County ranks #44 of 44 Idaho counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Clark County had?
FEMA records 4 federal disaster declarations for Clark County since 2005, most often 2 for biological events and 1 for fire events. The most recent was Covid-19 Pandemic, declared in April 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. Clark County's $1M EAL is a statistical average, not a guarantee for any specific year or address.