Harrison County, Mississippi Natural Disaster Risk
FEMA National Risk Index assessment · MS
HighComposite Risk Score
National percentile: 96th
Harrison County faces high composite natural disaster risk (NRI Risk Index score 95.6, 96th national percentile), driven primarily by hurricane and lightning exposure. Expected annual loss across all 18 hazard types is $155M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Harrison County carries a high composite natural disaster risk, with a National Risk Index score of 95.6 out of 100 — placing it in the 96th national percentile and in the upper tier of natural-disaster risk nationally. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in hurricane (tropical cyclones bringing extreme wind, rain, and storm surge) at Very High risk — $87M in expected annual loss and about 0.24 events per year; lightning (electrical discharges from storms that ignite fires and cause casualties) at Very High risk — $2M in expected annual loss and about 87.00 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at High risk — $11M in expected annual loss and about 0.75 events per year. Across all hazards, FEMA estimates $155M in expected annual loss for a population of 208K.
Beyond physical exposure, Harrison County has a high social vulnerability rating (how susceptible the population is to harm) and a high community resilience rating (its capacity to prepare for and recover from disasters). Higher vulnerability is partly offset by strong community resilience and recovery capacity.
The county's disaster history tells the same story: Harrison County has received 36 federal disaster declarations since 1965, including 24 for hurricane events and 6 for severe storm events. The most recent was Severe Winter Storm (winter storm), declared in February 2026.
Among 82 Mississippi counties, Harrison County ranks #1 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Hurricane | Very High | 0.24 / yr | $87M |
| Lightning | Very High | 87.00 / yr | $2M |
| Tornado | High | 0.75 / yr | $11M |
| Heat Wave | Medium | 13.72 / yr | $5M |
| Wildfire | Medium | 0.01 / yr | $3M |
| Coastal Flood | High | 6.48 / yr | $6M |
| Riverine Flood | Medium | 1.75 / yr | $33M |
| Cold Wave | Medium | 0.95 / yr | $5M |
| Hail | Medium | 1.92 / yr | $1M |
| Strong Wind | High | 1.60 / yr | $1M |
| Ice Storm | Medium | 0.58 / yr | $233K |
| Winter Weather | Medium | 0.84 / yr | $130K |
| Earthquake | Low | 0.00 / yr | $662K |
| Drought | Low | 18.70 / yr | $212K |
| Landslide | Very Low | 0.08 / yr | $317 |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Harrison County has received 36 federal disaster declarations since 1965, most recently Severe Winter Storm in February 2026. Most frequent causes: Hurricane (24), Severe Storm (6), Winter Storm (2).
| Declared | Type | Disaster |
|---|---|---|
| February 2026 | Winter Storm | Severe Winter Storm |
| January 2026 | Winter Storm | Severe Winter Storm |
| October 2021 | Hurricane | Hurricane Ida |
| August 2021 | Hurricane | Hurricane Ida |
| December 2020 | Hurricane | Hurricane Zeta |
| October 2020 | Hurricane | Hurricane Zeta |
| October 2020 | Hurricane | Hurricane Delta |
| September 2020 | Hurricane | Hurricane Sally |
| August 2020 | Hurricane | Hurricane Marco and Tropical Storm Laura |
| April 2020 | Biological | Covid-19 Pandemic |
Showing the 10 most recent of 36 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Harrison County?
Harrison County has a composite FEMA National Risk Index score of 95.6 out of 100, placing it in the High category and the 96th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Harrison County?
The three highest-rated hazards are Hurricane (Very High, $87M EAL), Lightning (Very High, $2M EAL), Tornado (High, $11M EAL). These account for most of the county's expected annual losses.
How does Harrison County compare to other Mississippi counties?
Harrison County ranks #1 of 82 Mississippi counties for overall natural disaster risk, with a high rating.
How many federally declared disasters has Harrison County had?
FEMA records 36 federal disaster declarations for Harrison County since 1965, most often 24 for hurricane events and 6 for severe storm events. The most recent was Severe Winter Storm, declared in February 2026.
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. Harrison County's $155M EAL is a statistical average, not a guarantee for any specific year or address.