Photo: Ascended Dreamer · CC BY-SA 4.0FEMA expects about as much hazard damage per building in Grand Isle as in the typical U.S. town, mostly from river and rain flooding
On FEMA’s National Risk Index, Grand Isle gets a B for hazard risk: lower expected damage per building than 56% of U.S. towns. Most of that expected damage is river and rain flooding (87%). Flood insurance has paid 3 claims here since 1986.
Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded
What Grand Isle faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
River and rain flooding
Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.
What’s behind Grand Isle’s grade
River and rain flooding is 87% of the building damage FEMA expects in Grand Isle, and Grand Isle’s rate of river and rain flooding damage is higher than 67% of U.S. census tracts. Lightning adds 3%, at a rate in the top 1% of U.S. census tracts.
B lower expected damage per building than 56% of U.S. towns (21,298).
All of Grand Isle’s residents live in one census tract; the figures are that tract’s.
In dollars, FEMA expects about $1.0M a year in losses across Grand Isle: $921K to buildings, the rest to people and crops.
Does Grand Isle flood? Rarely: 3 flood claims since 1986
Every paid claim on a federal flood insurance policy in Grand Isle, from FEMA’s records: 2.5 per 1,000 homes, fewer than 56% of the 13,809 U.S. towns with a flood insurance record.
Grand Isle isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Grand Isle County.2 federal disasters brought FEMA money to Grand Isle
Disasters that paid out in Grand Isle itself (aid to households or repair grants to the Town of Grand Isle), newest first, with that year’s flood claims.
- 2011Severe Storms and Flooding28 households applied for aid$4K aid approved$105K to the Town of Grand Isle for repairs1 flood claim paid that year
- 2001Snow$4K to the Town of Grand Isle for repairs
Grand Isle County has had 15 natural disasters declared by the President since 1953, most often severe storms, then floods.
Old photos of Grand Isle after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Grand Isle archive →Grand Isle and its neighbors
Grand Isle is 4th of the 5 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Milton | A−less damage than 76% | river and rain flooding | 23 |
| Georgia | A−less damage than 75% | river and rain flooding | 5 |
| South Hero | Bless damage than 56% | river and rain flooding | 9 |
| Grand Isle | Bless damage than 56% | river and rain flooding | 3 |
| Plattsburgh | Bless damage than 55% | river and rain flooding | 22 |
| North Hero | — | not graded yet | |
| St. Albans | — | not graded yet | |
Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.
Get ready for what Grand Isle faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Turn around at flooded roads: a foot of moving water can carry off a car.
- Flood insurance usually takes 30 days to start, so buy it before the forecast.
- Keep papers and medicines up high, in a grab-and-go bag.
- Look up the address on FEMA’s flood map.
- Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
- Get a flood insurance quote early: policies usually start 30 days after you buy.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Grand Isle
Is Grand Isle at risk for natural disasters?
On FEMA’s National Risk Index, Grand Isle has lower expected damage per building than 56% of U.S. towns: B for hazard risk. Most of the expected damage is river and rain flooding (87%). The figures are for the one census tract the town shares with its neighbors. This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Grand Isle flood?
Flood insurance has paid 3 claims in Grand Isle since 1986, $6K in all, or 2.5 per 1,000 homes, fewer than 56% of U.S. towns with a flood insurance record.
Is Grand Isle in a flood zone?
Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In Grand Isle County, 1.5% of all homes carry federal flood insurance.
How much is flood insurance in Grand Isle?
FEMA’s Community Rating System list shows no discount for Grand Isle’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Grand Isle?
By FEMA money that reached Grand Isle, Severe Storms and Flooding (2011): 28 households applied for aid, $4K approved, and $105K to the Town of Grand Isle for repairs.
Is Grand Isle at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (87%), and Grand Isle’s rate for it is higher than 67% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Grand Isle.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Grand Isle’s residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.