On FEMA’s figures, Derry faces less hazard damage per building than 85% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Derry gets an A for hazard risk: lower expected damage per building than 85% of U.S. towns, #324 of 1,037 in Pennsylvania. Most of that expected damage is river and rain flooding (94%). Flood insurance has paid 1 claim here since 2002.
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 Derry 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 Derry’s grade
River and rain flooding is 94% of the building damage FEMA expects in Derry, and Derry’s rate of river and rain flooding damage is lower than 54% of U.S. census tracts.
A #324 of 1,037 in Pennsylvania; lower expected damage per building than 85% of U.S. towns (21,298).
All of Derry’s residents live in one census tract; the figures are that tract’s.
The typical Pennsylvania town has lower expected damage than 71% of U.S. towns; within the state, Derry has less expected damage per building than 69% of Pennsylvania towns.
In dollars, FEMA expects about $420K a year in losses across Derry: $358K to buildings, the rest to people and crops.
Does Derry flood? Rarely: 1 flood claim since 2002
Every paid claim on a federal flood insurance policy in Derry, from FEMA’s records: 0.7 per 1,000 homes, fewer than 84% of the 13,809 U.S. towns with a flood insurance record.
Derry isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Westmoreland County.1 federal disaster brought FEMA money to Derry
Disasters that paid out in Derry itself (aid to households or repair grants to the Borough of Derry), newest first, with that year’s flood claims.
- 2004Tropical Depression Ivan8 households applied for aid$29K aid approved
Westmoreland County has had 17 natural disasters declared by the President since 1953, most often floods, then winter storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Derry after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Derry archive →Get ready for what Derry 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 Derry
Is Derry at risk for natural disasters?
On FEMA’s National Risk Index, Derry has lower expected damage per building than 85% of U.S. towns: A for hazard risk, #324 of 1,037 in Pennsylvania. Most of the expected damage is river and rain flooding (94%). 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 Derry flood?
Flood insurance has paid 1 claim in Derry since 2002, $543 in all, or 0.7 per 1,000 homes, fewer than 84% of U.S. towns with a flood insurance record.
Is Derry 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 Westmoreland County, 21% of homes in mapped flood zones carry federal flood insurance, and 0.5% of all homes do.
How much is flood insurance in Derry?
FEMA’s Community Rating System list shows no discount for Derry’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 Derry?
By FEMA money that reached Derry, Tropical Depression Ivan (2004): 8 households applied for aid, $29K approved.
Is Derry at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (94%), and Derry’s rate for it is lower than 54% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Derry.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Derry’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.