Photo: Paulo Ordoveza from Washington, DC · CC BY 2.0On FEMA’s figures, Derry Township faces less hazard damage per building than 80% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Derry Township gets an A− for hazard risk: lower expected damage per building than 80% of U.S. towns, #394 of 1,037 in Pennsylvania. Most of that expected damage is river and rain flooding (76%), then hurricanes (13%). Flood insurance has paid 181 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 Derry Township’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Derry Township 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 Derry Township’s grade
River and rain flooding is 76% of the building damage FEMA expects in Derry Township, and Derry Township’s rate of river and rain flooding damage is lower than 62% of U.S. census tracts. Next is hurricanes at 13% (higher than 81% of U.S. census tracts).
A− #394 of 1,037 in Pennsylvania; lower expected damage per building than 80% of U.S. towns (21,298).
Derry Township’s residents live in 7 census tracts; FEMA’s figures are combined by where they live.
The typical Pennsylvania town has lower expected damage than 71% of U.S. towns; within the state, Derry Township has less expected damage per building than 62% of Pennsylvania towns.
In dollars, FEMA expects about $6.7M a year in losses across Derry Township: $5.5M to buildings, the rest to people and crops.
Does Derry Township flood? Yes: 181 flood claims since 1978
Every paid claim on a federal flood insurance policy in Derry Township, from FEMA’s records: 17.4 per 1,000 homes, more than 82% of the 13,809 U.S. towns with a flood insurance record.
- Tropical Storm Lee30 claims · $1.5M
- Tropical Storm Ivan28 claims · $748K
Derry Township isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Dauphin County.The storms Derry Township remembers
None of the 17 disasters declared for Dauphin County shows FEMA aid or repair money reaching Derry Township itself in FEMA’s records, so these are its biggest flood-claim years.
- 201130 flood claims paidThe year of Tropical Storm Lee, declared for Dauphin County
- 199629 flood claims paidThe year of Severe Storms and Flooding, declared for Dauphin County
- 200428 flood claims paidThe year of Tropical Depression Ivan, declared for Dauphin County
Dauphin 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 Township after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Derry Township archive →Derry Township and its neighbors
Derry Township is 2nd of the 8 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 |
|---|---|---|---|
| Palmyra | Aless damage than 89% | river and rain flooding | 3 |
| Derry Township | A−less damage than 80% | river and rain flooding | 181 |
| Lower Swatara Township | A−less damage than 77% | river and rain flooding | 91 |
| Swatara Township | B+less damage than 72% | river and rain flooding | 312 |
| North Londonderry Township | Bless damage than 65% | river and rain flooding | 9 |
| East Hanover Township | Bless damage than 58% | river and rain flooding | 62 |
| South Hanover Township | B−more damage than 50% | river and rain flooding | 106 |
| Hummelstown | B−more damage than 55% | river and rain flooding | 56 |
| Hershey | — | a Census area inside a town; graded with the town | |
| Union Deposit | — | 808 residents; we grade 1,000+ | |
| Palmdale | — | 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 Derry Township 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 Derry Township
Is Derry Township at risk for natural disasters?
On FEMA’s National Risk Index, Derry Township has lower expected damage per building than 80% of U.S. towns: A− for hazard risk, #394 of 1,037 in Pennsylvania. Most of the expected damage is river and rain flooding (76%) and hurricanes (13%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Derry Township flood?
Flood insurance has paid 181 claims in Derry Township since 1978, $4.3M in all, or 17.4 per 1,000 homes, more than 82% of U.S. towns with a flood insurance record. 24 properties have flooded more than once. The most claims came from Tropical Storm Lee (30).
Is Derry Township 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 Dauphin County, 26% of homes in mapped flood zones carry federal flood insurance, and 1.2% of all homes do.
How much is flood insurance in Derry Township?
FEMA’s Community Rating System list shows no discount for Derry Township’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 Township?
By flood claims, Tropical Storm Lee: 30 paid, $1.5M.
Is Derry Township at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (76%), and Derry Township’s rate for it is lower than 62% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Derry Township.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Derry Township’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.