Lewis and Clark County
Montana — Natural Disaster Risk Assessment
LowComposite Risk Score
National percentile: 71th
Lewis and Clark County faces low composite natural disaster risk (NRI Risk Index score 71.2, 71th national percentile), driven primarily by winter weather and landslide exposure. Expected annual loss across all 18 hazard types is $35M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Winter Weather | Very High | 43.82 / yr | $2M |
| Landslide | Medium | 2.20 / yr | $154K |
| Cold Wave | High | 6.33 / yr | $13M |
| Wildfire | Medium | 0.00 / yr | $3M |
| Earthquake | Low | 0.01 / yr | $4M |
| Avalanche | Medium | 0.03 / yr | $457K |
| Lightning | Medium | 24.56 / yr | $504K |
| Riverine Flood | Low | 1.07 / yr | $12M |
| Heat Wave | Very Low | 0.70 / yr | $213K |
| Drought | Very Low | 76.10 / yr | $9K |
| Strong Wind | Low | 0.51 / yr | $226K |
| Ice Storm | Very Low | 0.01 / yr | $12K |
| Hail | Very Low | 0.77 / yr | $38K |
| Tornado | Very Low | 0.08 / yr | $62K |
| 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 |
Frequently Asked Questions
What is the overall natural disaster risk for Lewis and Clark County?
Lewis and Clark County has a composite FEMA National Risk Index score of 71.2 out of 100, placing it in the Low category and the 71th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Lewis and Clark County?
The three highest-rated hazards are Winter Weather (Very High, $2M EAL), Landslide (Medium, $154K EAL), Cold Wave (High, $13M EAL). These account for most of the county's expected annual losses.
How does Lewis and Clark County compare to other Montana counties?
Lewis and Clark County ranks #7 of 56 Montana counties for overall natural disaster risk, with a low rating.
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. Lewis and Clark County's $35M EAL is a statistical average, not a guarantee for any specific year or address.