Photo: Victor-ny · CC BY-SA 3.0FEMA puts Groton’s expected hazard damage per building below that of 77% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Groton gets an A− for hazard risk: lower expected damage per building than 77% of U.S. towns, #3 of 155 in Connecticut. Most of that expected damage is river and rain flooding (52%), then hurricanes (39%). Flood insurance has paid 61 claims here since 1978.
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 stands out about Groton’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Groton 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
Hurricanes
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 Groton’s grade
River and rain flooding is 52% of the building damage FEMA expects in Groton, and Groton’s rate of river and rain flooding damage is lower than 85% of U.S. census tracts. Coastal flooding adds 4%, at a rate in the top 5% of U.S. census tracts.
A− #3 of 155 in Connecticut; lower expected damage per building than 77% of U.S. towns (21,298).
Groton’s residents live in 4 census tracts; FEMA’s figures are combined by where they live.
The typical Connecticut town has higher expected damage than 62% of U.S. towns; within the state, Groton has less expected damage per building than 99% of Connecticut towns.
In dollars, FEMA expects about $1.6M a year in losses across Groton: $1.5M to buildings, the rest to people and crops.
Does Groton flood? Sometimes: 61 flood claims since 1978
Every paid claim on a federal flood insurance policy in Groton, from FEMA’s records: 11.9 per 1,000 homes, more than 77% of the 13,809 U.S. towns with a flood insurance record.
- Hurricane Sandy34 claims · $888K
- The March 2010 nor’easter6 claims · $52K
- Hurricane Gloria3 claims · $6K
Groton isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: the county.4 federal disasters brought FEMA money to Groton
Disasters that paid out in Groton itself (aid to households or repair grants to the City of Groton), newest first, with that year’s flood claims.
- 2021Remnants of Hurricane Ida9 households applied for aid$2K aid approved
- 2012Hurricane Sandy139 households applied for aid$84K aid approved34 flood claims paid for it, $888K
- 2011Tropical Storm Irene45 households applied for aid$17K aid approved2 flood claims paid for it, $24K
- 2010Severe Storms and Flooding244 households applied for aid$353K aid approved6 flood claims paid that year
Old photos of Groton after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Groton archive →Groton and its neighbors
Groton has the lowest expected damage per building of the 3 graded towns here. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Groton | A−less damage than 77% | river and rain flooding | 61 |
| Groton | Bless damage than 62% | river and rain flooding | 105 |
| New London | B−less damage than 51% | river and rain flooding | 139 |
| Conning Towers-Nautilus Park | — | a Census area inside a town; graded with the town | |
| Long Hill | — | a Census area inside a town; graded with the town | |
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 Groton 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.
- The season runs June through November and peaks from mid-August to mid-October.
- Bring in porch furniture and anything the wind can throw.
- Fill the gas tank and charge phones before the storm arrives.
- 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 Groton
Is Groton at risk for natural disasters?
On FEMA’s National Risk Index, Groton has lower expected damage per building than 77% of U.S. towns: A− for hazard risk, #3 of 155 in Connecticut. Most of the expected damage is river and rain flooding (52%) and hurricanes (39%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Groton flood?
Flood insurance has paid 61 claims in Groton since 1978, $1.1M in all, or 11.9 per 1,000 homes, more than 77% of U.S. towns with a flood insurance record. 4 properties have flooded more than once. The most claims came from Hurricane Sandy (34).
Is Groton 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 the county, 61% of homes in mapped flood zones carry federal flood insurance, and 2.6% of all homes do.
How much is flood insurance in Groton?
FEMA’s Community Rating System list shows no discount for Groton’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 Groton?
By FEMA money that reached Groton, Severe Storms and Flooding (2010): 244 households applied for aid, $353K approved. By flood claims, Hurricane Sandy: 34 paid, $888K.
Is Groton at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (52%), and Groton’s rate for it is lower than 85% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Groton.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Groton’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.