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

Jefferson County Disaster Risk

Jefferson County, Idaho

FEMA Risk Rating

Very Low

National Percentile

40th

of 3,144 counties

State Rank

#21

of 44 (1 = highest risk)

Flood Risk

37th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very Low

Higher than 37% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 63% of US counties

Tornado

Tornado and severe thunderstorm risk

Very Low

Higher than 7% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively Low

Higher than 81% of US counties

Risk Overview

About Natural Disaster Risk in Jefferson County, Idaho

Jefferson County faces very low national risk

Jefferson County's composite score of 40.11 and "Very Low" rating place it well below the national average for natural disaster exposure. This favorable profile reflects relatively balanced hazard exposure across most disaster types.

Jefferson County slightly outranks Idaho's average

At 40.11, Jefferson County scores just above the state average of 38.51, indicating near-average risk for Idaho. This puts the county in the safer half of Idaho's natural disaster landscape.

Comparable to neighboring rural counties

Jefferson County's 40.11 aligns closely with Jerome County (21.47) and Latah County (33.27), though it carries slightly higher overall risk. The county sits in Idaho's middle tier for natural disaster vulnerability.

Earthquake risk stands notably higher here

Earthquake risk scores 80.63—the county's most pressing hazard—while wildfire and flood risks remain moderate at 62.50 and 37.09 respectively. Tornado exposure is minimal at just 6.97.

Earthquake insurance deserves priority attention

With earthquake risk at 80.63, homeowners should evaluate whether their insurance includes earthquake coverage, as standard policies typically exclude it. Review your current policy and ask your agent about earthquake protection options.

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

Preparedness Guide

What to Prepare for in Jefferson County

Top Hazards by Exposure

  1. #1
    EarthquakePrepare
    81th percentile
  2. #2
    WildfirePrepare
    63th percentile
  3. #3
    FloodPrepare
    37th percentile

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

Local Resources

Risk Advisory: Jefferson County

Risk Verdict

Jefferson County's natural disaster risk is among the lowest in the country, with a composite score at the 40th percentile nationally. The 40th percentile national ranking is one lens; Jefferson County residents also benefit from reviewing which specific hazard types drive the county's composite score and preparing accordingly.

Hazard Breakdown

Earthquake risk is Jefferson County's dominant natural hazard, ranked at the 81th percentile nationally under FEMA's National Risk Index. Wildfire ranks second at the 63th percentile nationally. Additional tracked hazards include flood (37th percentile), tornado (7th percentile).

Preparedness Context

Earthquake risk is Jefferson County's leading natural hazard, ranked at the 81th percentile nationally. Securing tall furniture, water heaters, and bookcases to walls with anti-tip hardware is among the simplest and most effective life-safety measures households can take. The county's wildfire risk at the 63th percentile nationally is a seasonal consideration alongside the year-round earthquake threat, requiring awareness of both hazard types. Jefferson County residents should locate the main gas shutoff valve and keep an appropriate wrench nearby — gas leaks cause a significant share of earthquake-related injuries and fires, and the shutoff step is safe to take immediately after shaking stops.

Regional Context

At just 1.6 composite points from the Idaho average, Jefferson County's natural disaster risk is closely in line with its in-state peers.

Is your household prepared for Jefferson 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 Jefferson County, ID?
Jefferson County has a FEMA National Risk Index rating of Very Low, placing it in the 40th 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 Jefferson County?
Jefferson County is evaluated for five major natural hazard types: earthquake (81th percentile), wildfire (63th percentile), flooding (37th percentile), tornado (7th percentile). The highest-risk hazard is earthquake at the 81th 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 Jefferson County risk compare to the Idaho average?
Jefferson County's composite risk percentile is 40th, compared to the Idaho state average of 39th percentile. The state's overall risk rating is Very Low. This means Jefferson County faces higher natural disaster risk than the typical county in Idaho.
Is Jefferson County at risk for earthquake?
Yes, Jefferson County's earthquake risk is at the 81th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Jefferson County is at the 37th 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 Jefferson County higher risk than average?
Jefferson County's composite risk score of 40th percentile is above the Idaho state average of 39th percentile. This elevated risk is driven by earthquake exposure (81th percentile), along with wildfire 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

Adams County

Idaho

-0.5

Very Low

40th percentile

Lemhi County

Idaho

+1.3

Very Low

41th percentile

Fremont County

Idaho

-1.8

Very Low

38th 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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