West Dennis Graded School · Photo: Thomas Kelley from Boston, MA · CC BY-SA 2.0Dennis’s building-damage rate from coastal flooding is in the top 2% of U.S. census tracts
On FEMA’s National Risk Index, Dennis gets a B− for hazard risk: lower expected damage per building than 50% of U.S. towns, #237 of 283 in Massachusetts. Most of that expected damage is river and rain flooding (56%), then hurricanes (23%). Flood insurance has paid 200 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 Dennis’ natural hazards
From FEMA’s model and FEMA’s records, below.
What Dennis 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
Coastal 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 Dennis’ grade
River and rain flooding is 56% of the building damage FEMA expects in Dennis, and Dennis’ rate of river and rain flooding damage is lower than 57% of U.S. census tracts. Coastal flooding adds 18%, at a rate in the top 2% of U.S. census tracts.
B− #237 of 283 in Massachusetts; lower expected damage per building than 50% of U.S. towns (21,298).
Dennis’ residents live in 5 census tracts; FEMA’s figures are combined by where they live.
The typical Massachusetts town has lower expected damage than 76% of U.S. towns; within the state, Dennis has more expected damage per building than 84% of Massachusetts towns.
In dollars, FEMA expects about $6.1M a year in losses across Dennis: $5.9M to buildings, the rest to people and crops.
Does Dennis flood? Yes: 200 flood claims since 1978
Every paid claim on a federal flood insurance policy in Dennis, from FEMA’s records: 13.0 per 1,000 homes, more than 78% of the 13,809 U.S. towns with a flood insurance record.
- Hurricane Bob77 claims · $934K
- The December nor’easter14 claims · $510K
- The “Halloween” storm7 claims · $36K
Dennis isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Barnstable County.10 federal disasters brought FEMA money to Dennis
Disasters that paid out in Dennis itself (aid to households or repair grants to the Town of Dennis), newest first, with that year’s flood claims.
- 2018Severe Winter Storm and Flooding$266K to the Town of Dennis for repairs19 flood claims paid that year
- 2015Severe Winter Storm, Snowstorm, and Flooding$104K to the Town of Dennis for repairs1 flood claim paid that year
- 2013Severe Winter Storm, Snowstorm, and Flooding$92K to the Town of Dennis for repairs2 flood claims paid that year
- 2012Hurricane Sandy$97K to the Town of Dennis for repairs1 flood claim paid that year
- 2011Tropical Storm Irene$100K to the Town of Dennis for repairs1 flood claim paid for it, $3K
- 2010Hurricane Earl$26K to the Town of Dennis for repairs2 flood claims paid that year
Show all 10
- 2007Severe Storms and Inland and Coastal Flooding$49K to the Town of Dennis for repairs1 flood claim paid that year
- 2005Record And/or Near Record Snow$130K to the Town of Dennis for repairs2 flood claims paid that year
- 2003Snow$26K to the Town of Dennis for repairs
- 2003Snow$57K to the Town of Dennis for repairs
Barnstable County has had 18 natural disasters declared by the President since 1953, most often hurricanes and tropical storms, then winter storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Dennis after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Dennis archive →Dennis and its neighbors
Dennis is 2nd of the 4 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 |
|---|---|---|---|
| Brewster | A−less damage than 76% | river and rain flooding | 13 |
| Dennis | B−less damage than 50% | river and rain flooding | 200 |
| Yarmouth | B−more damage than 53% | river and rain flooding | 169 |
| Harwich | C+more damage than 55% | river and rain flooding | 40 |
| East Dennis | — | a Census area inside a town; graded with the town | |
| Yarmouth Port | — | a Census area inside a town; graded with the town | |
| Dennis Port | — | a Census area inside a town; graded with the town | |
| South Yarmouth | — | a Census area inside a town; graded with the town | |
| West Dennis | — | a Census area inside a town; graded with the town | |
| South Dennis | — | a Census area inside a town; graded with the town | |
| Northwest Harwich | — | 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 Dennis 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.
- Know your evacuation zone and the way off the coast.
- Storm surge comes fast: leave when you’re told, not when the water arrives.
- Move cars to high ground before king tides and nor’easters.
- 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 Dennis
Is Dennis at risk for natural disasters?
On FEMA’s National Risk Index, Dennis has lower expected damage per building than 50% of U.S. towns: B− for hazard risk, #237 of 283 in Massachusetts. Most of the expected damage is river and rain flooding (56%) and hurricanes (23%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Dennis flood?
Flood insurance has paid 200 claims in Dennis since 1978, $2.2M in all, or 13.0 per 1,000 homes, more than 78% of U.S. towns with a flood insurance record. 19 properties have flooded more than once. The most claims came from Hurricane Bob (77).
Is Dennis 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 Barnstable County, 40% of homes in mapped flood zones carry federal flood insurance, and 5.4% of all homes do.
How much is flood insurance in Dennis?
FEMA’s Community Rating System list shows no discount for Dennis’ 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 Dennis?
By FEMA money that reached Dennis, Severe Winter Storm and Flooding (2018): $266K to the Town of Dennis for repairs. By flood claims, Hurricane Bob: 77 paid, $934K.
Is Dennis at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (56%), and Dennis’ rate for it is lower than 57% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Dennis.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Dennis’ 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.