Photo: Canadian2006 · CC BY-SA 3.0FEMA expects less hazard damage per building in Slippery Rock than almost anywhere in the U.S., mostly from river and rain flooding
On FEMA’s National Risk Index, Slippery Rock gets an A+ for hazard risk: among the lowest expected damage per building of U.S. towns, #6 of 1,037 in Pennsylvania. Most of that expected damage is river and rain flooding (83%). Flood insurance has paid 2 claims here since 1996.
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 Slippery Rock 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
Tornadoes
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 Slippery Rock’s grade
River and rain flooding is 83% of the building damage FEMA expects in Slippery Rock, and Slippery Rock’s rate of river and rain flooding damage is lower than 95% of U.S. census tracts. Next is tornadoes at 8% (lower than 53% of U.S. census tracts).
A+ #6 of 1,037 in Pennsylvania; among the lowest expected damage per building of U.S. towns (21,298).
All of Slippery Rock’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, Slippery Rock has less expected damage per building than 100% of Pennsylvania towns.
In dollars, FEMA expects about $522K a year in losses across Slippery Rock: $455K to buildings, the rest to people and crops.
Does Slippery Rock flood? Rarely: 2 flood claims since 1996
Every paid claim on a federal flood insurance policy in Slippery Rock, from FEMA’s records: 1.3 per 1,000 homes, fewer than 73% of the 13,809 U.S. towns with a flood insurance record.
Slippery Rock isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Butler County.2 federal disasters brought FEMA money to Slippery Rock
Disasters that paid out in Slippery Rock itself (aid to households or repair grants to the Borough of Slippery Rock), newest first, with that year’s flood claims.
- 2004Tropical Depression Ivan13 households applied for aid$64K aid approved
- 2004Severe Storms and Flooding Associated with Tropical Depression Frances15 households applied for aid$25K aid approved
Butler County has had 8 natural disasters declared by the President since 1953, most often floods, then hurricanes and tropical storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Slippery Rock after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Slippery Rock archive →Slippery Rock and its neighbors
Slippery Rock has the lowest expected damage per building of the 1 graded towns here. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Slippery Rock | A+among the lowest damage | river and rain flooding | 2 |
| Slippery Rock University | — | 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 Slippery Rock 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.
- Pick your spot now: the lowest floor, an inside room, no windows.
- A watch means be ready; a warning means take cover now.
- Keep shoes and a flashlight by the bed.
- 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 Slippery Rock
Is Slippery Rock at risk for natural disasters?
On FEMA’s National Risk Index, Slippery Rock has among the lowest expected damage per building of U.S. towns: A+ for hazard risk, #6 of 1,037 in Pennsylvania. Most of the expected damage is river and rain flooding (83%) and tornadoes (8%). 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 Slippery Rock flood?
Flood insurance has paid 2 claims in Slippery Rock since 1996, $20K in all, or 1.3 per 1,000 homes, fewer than 73% of U.S. towns with a flood insurance record.
Is Slippery Rock 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 Butler County, 20% of homes in mapped flood zones carry federal flood insurance, and 0.5% of all homes do.
How much is flood insurance in Slippery Rock?
FEMA’s Community Rating System list shows no discount for Slippery Rock’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 Slippery Rock?
By FEMA money that reached Slippery Rock, Tropical Depression Ivan (2004): 13 households applied for aid, $64K approved.
Is Slippery Rock at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (83%), and Slippery Rock’s rate for it is lower than 95% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Slippery Rock.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Slippery Rock’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.