Lewis County, Missouri Natural Disaster Risk
FEMA National Risk Index assessment · MO
Very LowComposite Risk Score
National percentile: 27th
Lewis County faces very low composite natural disaster risk (NRI Risk Index score 27.4, 27th national percentile), driven primarily by heat wave and landslide exposure. Expected annual loss across all 18 hazard types is $8M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Lewis County is very low, with a National Risk Index score of 27.4 out of 100 — placing it in the 27th 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.
The county's risk is driven primarily by heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at Medium risk — $2M in expected annual loss and about 8.42 events per year; landslide (downhill movement of rock, soil, and debris on unstable slopes) at Low risk — $3K in expected annual loss and about 0.19 events per year; and drought (extended dry periods that stress water supplies and agriculture) at Low risk — $287K in expected annual loss and about 6.73 events per year. Across all hazards, FEMA estimates $8M in expected annual loss for a population of 10K.
Beyond physical exposure, Lewis County has a medium social vulnerability rating (how susceptible the population is to harm) and a 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 federal record bears this out: Lewis County has received 26 federal disaster declarations since 1965, including 15 for severe storm events and 5 for flood events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 115 Missouri counties, Lewis County ranks #90 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Heat Wave | Medium | 8.42 / yr | $2M |
| Landslide | Low | 0.19 / yr | $3K |
| Drought | Low | 6.73 / yr | $287K |
| Hail | Low | 3.43 / yr | $326K |
| Strong Wind | Medium | 4.01 / yr | $622K |
| Lightning | Low | 47.29 / yr | $151K |
| Earthquake | Very Low | 0.00 / yr | $124K |
| Riverine Flood | Low | 1.46 / yr | $4M |
| Wildfire | Very Low | 0.00 / yr | $19K |
| Cold Wave | Low | 4.37 / yr | $509K |
| Tornado | Low | 0.29 / yr | $536K |
| Winter Weather | Very Low | 10.37 / yr | $16K |
| Ice Storm | Very Low | 0.72 / yr | $14K |
| Hurricane | Very Low | 0.01 / yr | $2K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Lewis County has received 26 federal disaster declarations since 1965, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Severe Storm (15), Flood (5), Severe Ice Storm (3).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| July 2019 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| January 2016 | Flood | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| August 2015 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| October 2014 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| July 2013 | Severe Storm | Severe Storms, Straight-Line Winds, Tornadoes, and Flooding |
| June 2011 | Flood | Flooding |
| March 2011 | Severe Storm | Severe Winter Storm and Snowstorm |
| February 2011 | Severe Storm | Severe Winter Storm |
Showing the 10 most recent of 26 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Lewis County?
Lewis County has a composite FEMA National Risk Index score of 27.4 out of 100, placing it in the Very Low category and the 27th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Lewis County?
The three highest-rated hazards are Heat Wave (Medium, $2M EAL), Landslide (Low, $3K EAL), Drought (Low, $287K EAL). These account for most of the county's expected annual losses.
How does Lewis County compare to other Missouri counties?
Lewis County ranks #90 of 115 Missouri counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Lewis County had?
FEMA records 26 federal disaster declarations for Lewis County since 1965, most often 15 for severe storm events and 5 for flood events. The most recent was Covid-19 Pandemic, declared in March 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. Lewis County's $8M EAL is a statistical average, not a guarantee for any specific year or address.