Photo: Kenneth C. Zirkel · CC BY 4.0FEMA expects less hazard damage per building in Dedham than in 87% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Dedham gets an A for hazard risk: lower expected damage per building than 87% of U.S. towns, #68 of 283 in Massachusetts. Most of that expected damage is river and rain flooding (77%), then hurricanes (13%). Flood insurance has paid 30 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 Dedham’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Dedham 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
Earthquakes
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 Dedham’s grade
River and rain flooding is 77% of the building damage FEMA expects in Dedham, and Dedham’s rate of river and rain flooding damage is lower than 70% of U.S. census tracts. Next is hurricanes at 13% (higher than 79% of U.S. census tracts).
A #68 of 283 in Massachusetts; lower expected damage per building than 87% of U.S. towns (21,298).
Dedham’s residents live in 6 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, Dedham has less expected damage per building than 76% of Massachusetts towns.
In dollars, FEMA expects about $4.7M a year in losses across Dedham: $4.3M to buildings, the rest to people and crops.
Does Dedham flood? Sometimes: 30 flood claims since 1978
Every paid claim on a federal flood insurance policy in Dedham, from FEMA’s records: 2.8 per 1,000 homes, fewer than 54% of the 13,809 U.S. towns with a flood insurance record.
- The March 2010 nor’easter13 claims · $165K
Dedham isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Norfolk County.11 federal disasters brought FEMA money to Dedham
Disasters that paid out in Dedham itself (aid to households or repair grants to the Town of Dedham), newest first, with that year’s flood claims.
- 2018Severe Winter Storm and Snowstorm$144K to the Town of Dedham for repairs
- 2015Severe Winter Storm, Snowstorm, and Flooding$344K to the Town of Dedham for repairs
- 2013Severe Winter Storm, Snowstorm, and Flooding$194K to the Town of Dedham for repairs
- 2011Tropical Storm Irene$146K to the Town of Dedham for repairs
- 2011Severe Winter Storm and Snowstorm$169K to the Town of Dedham for repairs
- 2010Severe Storms and Flooding353 households applied for aid$537K aid approved$60K to the Town of Dedham for repairs13 flood claims paid that year
Show all 11
- 2005Record And/or Near Record Snow$322K to the Town of Dedham for repairs
- 2004Flooding4 households applied for aid$2K aid approved
- 2003Snow$169K to the Town of Dedham for repairs
- 2003Snow$94K to the Town of Dedham for repairs
- 2001Snow$89K to the Town of Dedham for repairs1 flood claim paid that year
Norfolk County has had 29 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 Dedham after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Dedham archive →Dedham and its neighbors
Dedham 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 |
|---|---|---|---|
| Westwood | Aless damage than 95% | river and rain flooding | 27 |
| Boston | Aless damage than 92% | river and rain flooding | 209 |
| Canton | Aless damage than 90% | river and rain flooding | 26 |
| Dedham | Aless damage than 87% | river and rain flooding | 30 |
| Needham | Aless damage than 85% | river and rain flooding | 34 |
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 Dedham 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.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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 Dedham
Is Dedham at risk for natural disasters?
On FEMA’s National Risk Index, Dedham has lower expected damage per building than 87% of U.S. towns: A for hazard risk, #68 of 283 in Massachusetts. Most of the expected damage is river and rain flooding (77%) and hurricanes (13%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Dedham flood?
Flood insurance has paid 30 claims in Dedham since 1978, $231K in all, or 2.8 per 1,000 homes, fewer than 54% of U.S. towns with a flood insurance record. 1 properties have flooded more than once. The most claims came from March 2010 Nor'easter (13).
Is Dedham 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 Norfolk County, 43% of homes in mapped flood zones carry federal flood insurance, and 1.5% of all homes do.
How much is flood insurance in Dedham?
FEMA’s Community Rating System list shows no discount for Dedham’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 Dedham?
By FEMA money that reached Dedham, Severe Storms and Flooding (2010): 353 households applied for aid, $537K approved, and $60K to the Town of Dedham for repairs. By flood claims, March 2010 Nor'easter: 13 paid, $165K.
Is Dedham at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (77%), and Dedham’s rate for it is lower than 70% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Dedham.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Dedham’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.