riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Lemhi County Disaster Risk

Lemhi County, Idaho

FEMA Risk Rating

Very Low

National Percentile

41th

of 3,144 counties

State Rank

#20

of 44 (1 = highest risk)

Flood Risk

60th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Relatively Low

Higher than 60% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Moderate

Higher than 93% of US counties

Tornado

Tornado and severe thunderstorm risk

Very Low

Higher than 3% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively Low

Higher than 53% of US counties

Risk Overview

About Natural Disaster Risk in Lemhi County, Idaho

Lemhi County carries very low national risk

Lemhi County's composite score of 41.44 and "Very Low" rating position it well below the national average for natural disaster exposure. The county's hazard profile remains relatively manageable overall.

Lemhi County slightly exceeds Idaho's average

At 41.44, Lemhi County scores just above the state average of 38.51, placing it in the middle range of Idaho's 44 counties. This positions the county as relatively typical for the state.

Lemhi County moderately outranks similar counties

Lemhi County's 41.44 exceeds Jerome County (21.47) and Lincoln County (9.06), but trails Idaho County (78.37) significantly. The county sits in Idaho's safer-than-average tier.

Wildfire and flood are primary concerns

Wildfire risk reaches 93.19 and flood risk scores 59.76—the county's two most serious hazards. Earthquake exposure is moderate at 53.47, while tornado risk remains minimal at 3.15.

Wildfire and flood coverage are non-negotiable

With wildfire at 93.19 and flood risk at 59.76, homeowners must secure both wildfire and flood insurance policies. Standard homeowners coverage excludes both hazards, leaving gaps that must be filled.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Lemhi County

Top Hazards by Exposure

  1. #1
    WildfirePrepare
    93th percentile
  2. #2
    FloodPrepare
    60th percentile
  3. #3
    EarthquakePrepare
    53th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Local Resources

Risk Advisory: Lemhi County

Risk Verdict

Lemhi County sits in the lower tier of U.S. counties for natural disaster exposure, ranked at the 41th percentile nationally. Lemhi County's 41th percentile ranking is favorable, though every county carries at least one natural hazard worth knowing — reviewing the specific risks listed above helps households focus their preparedness where it matters most.

Hazard Breakdown

Wildfire risk is Lemhi County's dominant natural hazard, ranked at the 93th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 60th percentile nationally. Additional tracked hazards include earthquake (53th percentile), tornado (3th percentile).

Preparedness Context

At the 93th percentile nationally for wildfire risk, Lemhi County households benefit from creating defensible space — a buffer of reduced vegetation around structures — and reviewing whether homeowners insurance covers wildfire damage in this region. Alongside wildfire, flood at the 60th percentile nationally means a multi-season preparedness mindset — fire season and flood or storm season often require different household plans. Enrolling in the county's wireless emergency alert system and keeping a vehicle at least half-full during peak fire season are low-cost habits that dramatically reduce evacuation lag time for Lemhi County residents.

Regional Context

Lemhi County tracks the Idaho county average closely, sitting 2.9 composite points above the state mean — neither a standout high-risk nor low-risk county within Idaho.

Is your household prepared for Lemhi County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Lemhi County, ID?
Lemhi County has a FEMA National Risk Index rating of Very Low, placing it in the 41th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect Lemhi County?
Lemhi County is evaluated for five major natural hazard types: wildfire (93th percentile), flooding (60th percentile), earthquake (53th percentile), tornado (3th percentile). The highest-risk hazard is wildfire at the 93th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does Lemhi County risk compare to the Idaho average?
Lemhi County's composite risk percentile is 41th, compared to the Idaho state average of 39th percentile. The state's overall risk rating is Very Low. This means Lemhi County faces higher natural disaster risk than the typical county in Idaho.
Is Lemhi County at risk for wildfire?
Yes, Lemhi County's wildfire risk is at the 93th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Lemhi County is at the 60th percentile.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Why is Lemhi County higher risk than average?
Lemhi County's composite risk score of 41th percentile is above the Idaho state average of 39th percentile. This elevated risk is driven by wildfire exposure (93th percentile), along with flooding and earthquake risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.

Counties with Similar Risk

Jefferson County

Idaho

-1.3

Very Low

40th percentile

Adams County

Idaho

-1.9

Very Low

40th percentile

Cassia County

Idaho

+2.1

Relatively Low

44th percentile

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.

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