St. Thomas Island, Virgin Islands Natural Disaster Risk
FEMA National Risk Index assessment · VI
Very LowComposite Risk Score
National percentile: 0th
St. Thomas Island faces very low composite natural disaster risk (NRI Risk Index score 0.0, 0th national percentile), driven primarily by a mix of natural hazards exposure. Expected annual loss across all 18 hazard types is $73M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
St. Thomas Island carries a very low composite natural disaster risk, with a National Risk Index score of 0.0 out of 100 — placing it in the 0th 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.
No individual hazard records measurable expected loss in St. Thomas Island in the current dataset, which keeps its overall expected annual loss low at $73M.
Beyond physical exposure, St. Thomas Island has a very low social vulnerability rating (how susceptible the population is to harm) and a very 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.
History supports the rating: St. Thomas Island has received 28 federal disaster declarations since 1970, including 17 for hurricane events and 3 for flood events. The most recent was Tropical Storm Ernesto (tropical storm), declared in October 2024.
Among 3 Virgin Islands counties, St. Thomas Island ranks #3 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.21 / yr | $79K |
| Cold Wave | Very Low | 0.00 / yr | $0 |
| Drought | Very Low | 0.00 / yr | $0 |
| Earthquake | Very Low | 0.07 / yr | $13M |
| Hail | Very Low | 0.00 / yr | $335 |
| Heat Wave | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.26 / yr | $40M |
| Ice Storm | Very Low | 0.00 / yr | $0 |
| Riverine Flood | Very Low | 0.79 / yr | $2M |
| Landslide | Very Low | 0.00 / yr | $0 |
| Lightning | Very Low | 0.00 / yr | $0 |
| Strong Wind | Very Low | 0.00 / yr | $333 |
| Tornado | Very Low | 0.00 / yr | $4K |
| Tsunami | Very Low | 0.04 / yr | $17M |
| Volcanic Activity | Very Low | 0.01 / yr | $995 |
| Wildfire | Very Low | 0.00 / yr | $0 |
| Winter Weather | Very Low | 0.00 / yr | $0 |
Disaster History
St. Thomas Island has received 28 federal disaster declarations since 1970, most recently Tropical Storm Ernesto in October 2024. Most frequent causes: Hurricane (17), Flood (3), Tropical Storm (2).
| Declared | Type | Disaster |
|---|---|---|
| October 2024 | Tropical Storm | Tropical Storm Ernesto |
| August 2024 | Tropical Storm | Tropical Storm Ernesto |
| July 2020 | Hurricane | Potential Tropical Cyclone Nine |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| August 2019 | Hurricane | Hurricane Dorian |
| September 2017 | Hurricane | Hurricane Maria |
| September 2017 | Hurricane | Hurricane Maria |
| September 2017 | Hurricane | Hurricane Irma |
| September 2017 | Hurricane | Hurricane Irma |
Showing the 10 most recent of 28 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for St. Thomas Island?
St. Thomas Island has a composite FEMA National Risk Index score of 0.0 out of 100, placing it in the Very Low category and the 0th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in St. Thomas Island?
The three highest-rated hazards are Avalanche (Very Low, $0 EAL), Coastal Flood (Very Low, $79K EAL), Cold Wave (Very Low, $0 EAL). These account for most of the county's expected annual losses.
How does St. Thomas Island compare to other Virgin Islands counties?
St. Thomas Island ranks #3 of 3 Virgin Islands counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has St. Thomas Island had?
FEMA records 28 federal disaster declarations for St. Thomas Island since 1970, most often 17 for hurricane events and 3 for flood events. The most recent was Tropical Storm Ernesto, declared in October 2024.
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. St. Thomas Island's $73M EAL is a statistical average, not a guarantee for any specific year or address.