Grand Isle County, Vermont Natural Disaster Risk
FEMA National Risk Index assessment · VT
Very LowComposite Risk Score
National percentile: 2th
Grand Isle County faces very low composite natural disaster risk (NRI Risk Index score 1.9, 2th national percentile), driven primarily by ice storm and hurricane exposure. Expected annual loss across all 18 hazard types is $4M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Grand Isle County carries a very low composite natural disaster risk, with a National Risk Index score of 1.9 out of 100 — placing it in the 2nd 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 ice storm (freezing rain that coats surfaces in heavy, damaging ice) at Low risk — $81K in expected annual loss and about 0.49 events per year; hurricane (tropical cyclones bringing extreme wind, rain, and storm surge) at Very Low risk — $40K in expected annual loss and about 0.02 events per year; and earthquake (ground shaking from sudden movement along geologic faults) at Very Low risk — $161K in expected annual loss and about 0.00 events per year. Across all hazards, FEMA estimates $4M in expected annual loss for a population of 7K.
Beyond physical exposure, Grand Isle County has a very low social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
History supports the rating: Grand Isle County has received 18 federal disaster declarations since 1973, including 6 for severe storm events and 4 for flood events. The most recent was Tropical Depression Debby (tropical storm), declared in August 2024.
Among 14 Vermont counties, Grand Isle County ranks #14 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Ice Storm | Low | 0.49 / yr | $81K |
| Hurricane | Very Low | 0.02 / yr | $40K |
| Earthquake | Very Low | 0.00 / yr | $161K |
| Lightning | Very Low | 22.47 / yr | $144K |
| Winter Weather | Very Low | 13.84 / yr | $31K |
| Heat Wave | Very Low | 2.16 / yr | $60K |
| Riverine Flood | Very Low | 0.43 / yr | $3M |
| Strong Wind | Very Low | 0.62 / yr | $172K |
| Landslide | Very Low | 0.02 / yr | $37 |
| Cold Wave | Very Low | 3.05 / yr | $90K |
| Tornado | Very Low | 0.01 / yr | $35K |
| Wildfire | Very Low | 0.00 / yr | $3K |
| Hail | Very Low | 0.89 / yr | $5K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Drought | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Grand Isle County has received 18 federal disaster declarations since 1973, most recently Tropical Depression Debby in August 2024. Most frequent causes: Severe Storm (6), Flood (4), Hurricane (3).
| Declared | Type | Disaster |
|---|---|---|
| August 2024 | Tropical Storm | Tropical Depression Debby |
| July 2023 | Flood | Severe Storms, Flooding, Landslides, and Mudslides |
| July 2023 | Flood | Flooding |
| March 2023 | Severe Storm | Severe Storm and Flooding |
| August 2021 | Hurricane | Tropical Storm Henri |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| July 2018 | Severe Storm | Severe Storm and Flooding |
| January 2018 | Severe Storm | Severe Storm and Flooding |
| January 2014 | Severe Ice Storm | Severe Winter Storms |
Showing the 10 most recent of 18 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Grand Isle County?
Grand Isle County has a composite FEMA National Risk Index score of 1.9 out of 100, placing it in the Very Low category and the 2th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Grand Isle County?
The three highest-rated hazards are Ice Storm (Low, $81K EAL), Hurricane (Very Low, $40K EAL), Earthquake (Very Low, $161K EAL). These account for most of the county's expected annual losses.
How does Grand Isle County compare to other Vermont counties?
Grand Isle County ranks #14 of 14 Vermont counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Grand Isle County had?
FEMA records 18 federal disaster declarations for Grand Isle County since 1973, most often 6 for severe storm events and 4 for flood events. The most recent was Tropical Depression Debby, declared in August 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. Grand Isle County's $4M EAL is a statistical average, not a guarantee for any specific year or address.