Photo: User:karthik_sripal · CC BY-SA 3.0On FEMA’s figures, Tredyffrin Township faces less hazard damage per building than 88% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Tredyffrin Township gets an A for hazard risk: lower expected damage per building than 88% of U.S. towns, #271 of 1,037 in Pennsylvania. Most of that expected damage is river and rain flooding (82%). Flood insurance has paid 79 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 Tredyffrin Township’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Tredyffrin 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
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 Tredyffrin Township’s grade
River and rain flooding is 82% of the building damage FEMA expects in Tredyffrin Township, and Tredyffrin Township’s rate of river and rain flooding damage is lower than 66% of U.S. census tracts. Next is hurricanes at 6% (higher than 67% of U.S. census tracts).
A #271 of 1,037 in Pennsylvania; lower expected damage per building than 88% of U.S. towns (21,298).
Tredyffrin 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, Tredyffrin Township has less expected damage per building than 74% of Pennsylvania towns.
In dollars, FEMA expects about $9.6M a year in losses across Tredyffrin Township: $7.6M to buildings, the rest to people and crops.
Does Tredyffrin Township flood? Sometimes: 79 flood claims since 1978
Every paid claim on a federal flood insurance policy in Tredyffrin Township, from FEMA’s records: 6.2 per 1,000 homes, more than 65% of the 13,809 U.S. towns with a flood insurance record.
- Tropical Storm Fred6 claims · $348K
- Hurricane Floyd5 claims · $44K
- Hurricane Ida5 claims · $423K
Tredyffrin 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: Chester County.The storms Tredyffrin Township remembers
None of the 21 disasters declared for Chester County shows FEMA aid or repair money reaching Tredyffrin Township itself in FEMA’s records, so these are its biggest flood-claim years.
- 201816 flood claims paidNo declaration for the county that year
- 202112 flood claims paidThe year of Remnants of Hurricane Ida, declared for Chester County
- 19997 flood claims paidThe year of Hurricane Floyd Major Disaster Declarations, declared for Chester County
Chester County has had 21 natural disasters declared by the President since 1953, most often severe storms, then hurricanes and tropical storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Tredyffrin Township after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Tredyffrin Township archive →Tredyffrin Township and its neighbors
Tredyffrin Township is 5th of the 7 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 |
|---|---|---|---|
| Easttown Township | A+less damage than 98% | river and rain flooding | 6 |
| East Whiteland Township | A+less damage than 98% | river and rain flooding | 17 |
| Willistown Township | A+less damage than 98% | river and rain flooding | 9 |
| Radnor Township | A+less damage than 96% | river and rain flooding | 103 |
| Tredyffrin Township | Aless damage than 88% | river and rain flooding | 79 |
| Schuylkill Township | A−less damage than 79% | river and rain flooding | 34 |
| Upper Merion Township | B+less damage than 67% | river and rain flooding | 93 |
| King of Prussia | — | a Census area inside a town; graded with the town | |
| Berwyn | — | a Census area inside a town; graded with the town | |
| Paoli | — | a Census area inside a town; graded with the town | |
| Devon | — | 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 Tredyffrin 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.
- 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 Tredyffrin Township
Is Tredyffrin Township at risk for natural disasters?
On FEMA’s National Risk Index, Tredyffrin Township has lower expected damage per building than 88% of U.S. towns: A for hazard risk, #271 of 1,037 in Pennsylvania. Most of the expected damage is river and rain flooding (82%) and hurricanes (6%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Tredyffrin Township flood?
Flood insurance has paid 79 claims in Tredyffrin Township since 1978, $2.4M in all, or 6.2 per 1,000 homes, more than 65% of U.S. towns with a flood insurance record. 15 properties have flooded more than once. The most claims came from Tropical Storm Fred (6).
Is Tredyffrin 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 Chester County, 40% of homes in mapped flood zones carry federal flood insurance, and 0.6% of all homes do.
How much is flood insurance in Tredyffrin Township?
FEMA’s Community Rating System list shows no discount for Tredyffrin 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 Tredyffrin Township?
By flood claims, Tropical Storm Fred: 6 paid, $348K.
Is Tredyffrin Township at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (82%), and Tredyffrin Township’s rate for it is lower than 66% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Tredyffrin Township.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Tredyffrin 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.