Hazard Plain Automated baseline

Butler County, PA

Risk-assessment baseline packet

County FIPS:
42019
Release:
2026-10
Data as of:
2026-09-30
Storm Events data through:
2026-06-30

Hazard Plain is an independent product built from public federal data. It is not a FEMA document and is not reviewed or endorsed by FEMA or any state agency.

Hazard Plain release 2026-10, as of 2026-09-30.

Summary

Plan status as of 2026-09-30: No county-level plan row in FEMA data.

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Inland Flooding ($41,302,325 a year), Tornado ($2,055,142) and Strong Wind ($1,524,618).

The tables that follow are organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B (B1-a to B2-c); each heading says which item its tables support.

Plan clock

No county-level plan row in FEMA data

What changed since your last plan

Not available. No county-level plan row in FEMA data, so there is no approval date to count from.

Sources: 1, 2, 4, 6 (numbered list at the end)

Plan status for every jurisdiction listed in this county: 57 rows, in the section "Plan clock: Plan status for every jurisdiction listed in this county" on the following pages.

State plan status and tribal plans in this state: see the state page.

Plan clock

Plan status for every jurisdiction listed in this county

Source: 1

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiryUpdate underwayNotes
Bruin boroughOrganized BoroughNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Butler cityCityApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Callery boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Cherry Valley boroughOrganized BoroughNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Chicora boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Connoquenessing boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
East Butler boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Eau Claire boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Evans City boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Fairview boroughOrganized BoroughNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Harmony boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Harrisville boroughOrganized BoroughNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Karns City boroughOrganized BoroughNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Mars boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Petrolia boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Portersville boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Prospect boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Saxonburg boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Seven Fields boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Slippery Rock boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Valencia boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
West Liberty boroughOrganized BoroughNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
West Sunbury boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Zelienople boroughOrganized BoroughApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Adams townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Allegheny townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Brady townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Buffalo townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Butler townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Center townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Cherry townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Clay townshipTownshipNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Clearfield townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Clinton townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Concord townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Connoquenessing townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Cranberry townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Donegal townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Fairview townshipTownshipNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Forward townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Franklin townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Jackson townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Jefferson townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Lancaster townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Marion townshipTownshipNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Mercer townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Middlesex townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Muddy Creek townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Oakland townshipTownshipNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Parker townshipTownshipNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Penn townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Slippery Rock townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Summit townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Venango townshipTownshipNo approved plan on recordnonenonenoneFEMA tracker shows a plan in progress
Washington townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress
Winfield townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleButler County Hazard Mitigation Plan (FEMA plan 107760), pending adoption here2021-11-23 by FEMA; not yet adopted here2026-11-22 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Worth townshipTownshipApproved, expires 2026-11-22Butler County Hazard Mitigation Plan (FEMA plan 107760)2021-11-232026-11-2253FEMA tracker shows a plan in progress

Supports FEMA checklist item B1-a: hazard identification

Hazards NRI does not cover (local data needed)

  • dam failure (incl. upstream dams)
  • levee failure
  • flash flood as its own subtype
  • ice jams
  • debris flows
  • erosion (riverine and coastal)
  • land subsidence and sinkholes
  • expansive soils

The 18 National Risk Index hazards, ranked by expected annual loss (EAL)

Sources: 5, 6

Rank by EALHazardNRI risk ratingEAL ratingEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL total (see note)modeled dollars per yearStorm Events records, 1996 to 2026-06-30countStorm Events coverage note
1Inland FloodingRelatively ModerateRelatively Moderate$41,153,132$12,496$136,696$41,302,325115
2TornadoRelatively LowRelatively Low$1,450,962$1,761$602,419$2,055,14217
3Strong WindRelatively ModerateRelatively Moderate$533,888$1,277$989,453$1,524,618491Includes 16 High Wind and 7 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
4LightningRelatively HighRelatively High$12,903n/a$1,380,784$1,393,6872
5EarthquakeVery LowRelatively Low$293,077n/a$66,035$359,112Storm Events does not record earthquakes.
6Heat WaveRelatively LowRelatively Lowunder $1$2,311$282,952$285,2630No recorded events in Storm Events since 1996 (data through 2026-06-30).
7Cold WaveVery LowRelatively Low$1,790$16,705$168,367$186,8629
8HurricaneVery LowRelatively Low$148,077$21,175$6,127$175,3800Declared 4 times; no Storm Events record of this type.
9Winter WeatherRelatively ModerateRelatively Moderate$107,080$25$31,729$138,83495
10HailVery LowVery Low$89,138$1,467$24,909$115,514170
11Ice StormRelatively LowRelatively Low$24,078n/a$88,707$112,78411
12LandslideRelatively LowRelatively Low$11,350n/a$19,163$30,5131
13WildfireVery LowVery Low$25,350$5$3,065$28,4200No recorded events in Storm Events since 1996 (data through 2026-06-30).
14DroughtNo RatingNo Expected Annual Lossesn/a$0n/a$02

Total = buildings + agriculture + population equivalence; FEMA values each expected death (or 10 injuries) at $13.7 million (2024 dollars).

NRI risk rating combines expected annual loss with social vulnerability and community resilience; EAL rating rates expected annual loss alone. Both compare this county with all U.S. counties.

Local data needed: state and local wildfire records (Storm Events records this hazard only in part).

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: avalanche, coastal flooding, tsunami and volcanic activity. That is the evidence for leaving them out of the plan.

The state hazard mitigation plan also lists hazards for this county; FEMA asks the plan to explain any hazard it leaves out.

Supports FEMA checklist item B1-b: hazard location

Affects the whole county (national data give no location within it): Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather.

Inland Flooding: The FEMA Flood Insurance Rate Map (FIRM) is the required location source for flooding. See the FEMA Flood Map Service Center (https://msc.fema.gov) for this county.

Hazards that vary within the county: highest-rated census tracts

Source: 5

HazardHighest-rated census tractsNRI risk rating, score 0 to 100
Earthquaketract 9104 (Relatively Low, 46.6); tract 9120.02 (Very Low, 38.7); tract 9128 (Very Low, 38.3)
Hurricanetract 9103.02 (Very Low, 49.8); tract 9111 (Very Low, 49.5); tract 9110 (Very Low, 49.3)
Landslidetract 9101 (Relatively Moderate, 96.4); tract 9118 (Relatively Moderate, 96.4); tract 9113 (Relatively Moderate, 95.7)
Tornadotract 9120.02 (Relatively Moderate, 54.4); tract 9103.02 (Relatively Low, 52.0); tract 9111 (Relatively Low, 51.5)
Wildfiretract 9118 (Relatively Low, 72.2); tract 9128 (Relatively Low, 72.1); tract 9120.02 (Relatively Low, 69.6)

Up to 3 census tracts per hazard, highest National Risk Index rating first, then highest score; a tract number is the Census tract number (for example 9104 is Census Tract 9104). FEMA's Resilience Analysis and Planning Tool maps the National Risk Index for every tract: https://www.fema.gov/emergency-managers/practitioners/resilience-analysis-and-planning-tool

Supports FEMA checklist item B1-c: hazard extent

Extent: scale, observed range and worst recorded event per hazard

Sources: 6, 7

HazardScaleRecordscount and yearsObserved rangeWorst recorded eventMost damaging (when different)How it applies to jurisdictionsNote
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill9 records, 2009 to 2026 (9 zone-level)1 day to 3 days (median 2 days); 9 with a recorded value3 consecutive days, 2025-01-20 to 2025-01-22, zone-levelCountywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage0
DroughtU.S. Drought Monitor scale (D0 to D4)2 records, 1999 (2 zone-level)61 days; 1 with a recorded value61 days (2 months), 1999-08-01 to 1999-09-30, a run of 2 consecutive Storm Events drought records, zone-levelCountywide (zone-level records).Storm Events enters a drought at D2 or worse east of the Rockies and D3 or worse from the Rockies west (NWS Instruction 10-1605); NRI drought counts D3 and D4 only.
EarthquakeModified Mercalli (local data)0Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hailhail size (inches)201 records, 1956 to 20260.75 in to 2.5 in (median 1 in); 201 with a recorded value2.5 in hail, 2020-03-28; same size also recorded on 2020-03-28Hail, 1994-07-29, $50,000 property; $500,000 crops (1994 dollars)Event records naming jurisdictions in the plan: Zelienople borough (14 records), Slippery Rock borough (12 records), Slippery Rock township (12 records), Butler city (10 records), Butler township (10 records), Mars borough (9 records), Portersville borough (7 records), Chicora borough (5 records), Harmony borough (5 records), West Liberty borough (4 records); and 13 more jurisdictions (see the Excel file).
Excessive Heat, Heatheat index (in event narratives)0
Hurricane, Tropical Storm, Tropical DepressionSaffir-Simpson0Storm Events files every zone of a storm's episode under the storm's type; flooding from the storm is filed as Flood or Flash Flood records.
Ice StormSperry-Piltz ice scale (local data)11 records, 1996 to 2016 (11 zone-level)Ice Storm, 1997-11-13, $5,000 property; crops not reported (1997 dollars); NWS zone PAZ014Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)115 records, 1996 to 2025 (12 zone-level)Flash Flood, 2019-05-28, $5,000,000 property; $100,000 crops (2019 dollars)Event records naming jurisdictions in the plan: Zelienople borough (10 records), Butler city (9 records), Butler township (9 records), Harmony borough (5 records), Evans City borough (4 records), Bruin borough (3 records), Chicora borough (3 records), Slippery Rock borough (3 records), Slippery Rock township (3 records), Callery borough (2 records); and 8 more jurisdictions (see the Excel file). Zone-level records (12) apply countywide.Flood depth: see the FEMA Flood Insurance Rate Map. Storm Events damage is often $0 or blank for floods, major ones included; FEMA Public Assistance by declaration (B1-d) shows which floods cost the most.
Debris Flownone (count and damage only)1 record, 2017No damage reported in 1 record.No event record names a jurisdiction in the plan.
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)2 records, 1996 to 1997Lightning, 1996-06-19, $10,000 property; crops not reported (1996 dollars)Event records naming jurisdictions in the plan: Mars borough (2 records).Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)23 records, 1999 to 2026 (23 zone-level)35 kt (40 mph) to 60 kt (69 mph) (median 50 kt (58 mph)); 21 with a recorded value60 kt (69 mph) estimated gust, High Wind, 2008-09-14; NWS zone PAZ014Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)583 records, 1961 to 202640 kt (46 mph) to 87 kt (100 mph) (median 50 kt (58 mph)); 405 with a recorded value87 kt (100 mph) estimated gust, Thunderstorm Wind, 2003-10-14, 6 direct injuriesThunderstorm Wind, 2024-08-06, $3,000,000 property; $0 crops (2024 dollars)Event records naming jurisdictions in the plan: Butler city (39 records), Butler township (39 records), Evans City borough (26 records), Slippery Rock borough (25 records), Slippery Rock township (25 records), Mars borough (23 records), Saxonburg borough (17 records), Zelienople borough (17 records), Harmony borough (10 records), Portersville borough (10 records); and 14 more jurisdictions (see the Excel file).
TornadoEnhanced Fujita (Fujita before Feb 2007)31 records, 1954 to 2026F/EF0 to F/EF3 (median F/EF0); 29 with a recorded valueF3 tornado, 1985-05-31, 22 mi path length (whole path, pre-1996), 243 yd wide, $25,000,000 property; crops not recorded (1985 dollars), 6 direct deaths, 80 direct injuriesEvent records naming jurisdictions in the plan: Prospect borough (3 records), West Liberty borough (2 records), Bruin borough (1 record), Butler city (1 record), Butler township (1 record), Callery borough (1 record), Mars borough (1 record), Muddy Creek township (1 record).Before 1996 a tornado is listed once, under the county where it began, with its whole path's rating and length; from 1996 on, each county lists its own segment. Length is not used to rank tornadoes (see Methods).
Wildfireacres burned (local data)0
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)95 records, 1996 to 2026 (95 zone-level)Winter Storm, 2008-02-01, $10,000 property; $0 crops (2008 dollars); NWS zone PAZ014Countywide (zone-level records).

Where a hazard names more than 10 jurisdictions, the table lists the 10 with the most records; every one is in the Excel file, sheet "B1-c Extent".

In event narratives only (local data needed): wind chill, temperature, heat index, ice thickness, acres burned and snow depth; any physical measure of debris flow and lightning.

Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records from zones that no NWS zone-county file places in this county (mostly before 2020) are not counted here (the Methods page explains the zone matching).

Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 11 declarations covering 8 separate hazard incidents counted in this packet (declarations for the same incident count once; non-natural and evacuation-only declarations are not counted).

No county-level plan row in FEMA data, so there is no approval date to count from.

Federal disaster declarations for this county

Sources: 1, 2, 3

DeclaredIncident beganFEMA numberTypeTitleMapped hazardCounty Public Assistancefederal share obligated, nominal dollarsNotes
2020-03-302020-01-20DR-4506-PAMajor disasterCOVID-19 PandemicNon-natural, not counted$8,278,428.07
2020-03-132020-01-20EM-3441-PAEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4506
2012-10-292012-10-26EM-3356-PAEmergencyHurricane SandyHurricaneno Public Assistance recorded
2010-04-162010-02-05DR-1898-PAMajor disasterSevere Winter Storms and SnowstormsWinter Weather$540,441.66
2005-09-102005-08-29EM-3235-PAEmergencyHurricane KatrinaHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2004-09-192004-09-17DR-1557-PAMajor disasterTropical Depression IvanHurricane$1,946,731.05
2004-09-192004-09-08DR-1555-PAMajor disasterSevere Storms and Flooding Associated with Tropical Depression FrancesHurricane; Inland FloodingPA not declared for this county
1996-01-211996-01-19DR-1093-PAMajor disasterSevere Storms and FloodingInland FloodingPA not declared for this county
1993-03-161993-03-13EM-3105-PAEmergencySevere Snowfall & Winter StormWinter Weatherno Public Assistance recorded
1980-08-191980-08-19DR-629-PAMajor disasterSevere Storms & FloodingInland Floodingno Public Assistance recorded
1972-06-231972-06-23DR-340-PAMajor disasterTropical Storm AgnesInland Flooding (primary); also designated: Hurricaneno Public Assistance recorded

County Public Assistance: applicants the FEMA record places in this county, including any state agencies FEMA files there; statewide rows are listed on the state page; federal share obligated, nominal dollars.

Statewide declarations

Source: 2

DeclaredIncident beganFEMA numberTypeTitleMapped hazard
2003-08-232003-07-21DR-1485-PAMajor disasterSevere Storms, Tornadoes, and FloodingInland Flooding; Tornado
1959-01-231959-01-23DR-89-PAMajor disasterFloodsInland Flooding
1956-08-091956-08-09DR-61-PAMajor disasterStormHazard not mapped (severe storm title names no single hazard); not counted
1956-05-211956-05-21DR-58-PAMajor disasterSevere StormHazard not mapped (severe storm title names no single hazard); not counted
1956-03-151956-03-15DR-51-PAMajor disasterFloodInland Flooding
1955-08-201955-08-20DR-40-PAMajor disasterFloods & RainsInland Flooding

FEMA recorded these with designated area Statewide and no county, so they are listed on every county page in the state and not counted with county rows. Local data needed: whether each one affected this county.

Public Assistance filed under this county for declarations that do not list it: 2 rows, $11,339.61

Sources: 2, 3

FEMA numberDeclaredTitleApplicantPA obligatedfederal share obligated, nominal dollars
DR-4149-PA2013-10-01Severe Storms, Tornadoes, and FloodingIrwin, Township of (Butler County)$5,184.80
DR-1485-PA2003-08-23Severe Storms, Tornadoes, and FloodingIrwin, Township of (Butler County)$6,154.81

FEMA's Public Assistance summaries file these applicants under this county, but FEMA's declaration rows for these disasters do not designate it (an electric cooperative or district serving several counties, for example). Not in any declaration row above and not counted.

Previous occurrences by hazard, with explicit no-event rows

Sources: 2, 6, 7

HazardStorm Events records, all years on file(years in the Period column)Since plan approvalrecordsIn the 12 months before plan approvalrecordsLast 5 yearsrecordsDeclared incidents, all yearsseparate disastersDeclared since approvalseparate disastersPeriodStatement
Cold Wave9301996 to 2026-06-30
Drought2001996 to 2026-06-30
Earthquake000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail2014301955 to 2026-06-30
Heat Wave0001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Hurricane0041996 to 2026-06-30No Storm Events records of this type; 4 federal declared incidents (see declarations table)
Ice Storm11001996 to 2026-06-30
Inland Flooding1152641996 to 2026-06-30
Landslide1001996 to 2026-06-30
Lightning2001996 to 2026-06-30
Strong Wind60615101955 to 2026-06-30Includes 16 High Wind and 7 Strong Wind records.
Tornado31701950 to 2026-06-30
Wildfire0001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Winter Weather953721996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2025-01-20Cold/Wind Chill$0 property; $0 crops (zone total, 2025 dollars)0, 0NWS zone PAZ014 (BUTLER), zone-levelwithin last 5 yearsB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
2024-08-06Thunderstorm Wind50 kt (58 mph) estimated gust$3,000,000 property; $0 crops (2024 dollars)0, 0BOYERSwithin last 5 yearsB1-c most damaging: Thunderstorm Wind
2020-03-28Hail2.5 indamage not reported0, 0CHICORAB1-c worst recorded: Hail
2019-05-28Flash Flood$5,000,000 property; $100,000 crops (2019 dollars)0, 0ZELIENOPLE to EIDENAUB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2015-06-12Thunderstorm Wind50 kt (58 mph) estimated gust$10,000 property; $0 crops (2015 dollars)1, 0JACKSVILLEdeaths or injuries recorded
2008-09-14High Wind60 kt (69 mph) estimated gust$5,000,000 property; $0 crops (zone total, 2008 dollars)0, 0NWS zone PAZ014 (BUTLER), zone-levelB1-c worst recorded: High Wind and Strong Wind
2008-02-01Winter Storm$10,000 property; $0 crops (zone total, 2008 dollars)0, 0NWS zone PAZ014 (BUTLER), zone-levelB1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2003-10-14Thunderstorm Wind87 kt (100 mph) estimated gust$1,000,000 property; crops not reported (2003 dollars)0, 6CRIDERS CORNERSdeaths or injuries recorded
1999-08-01Droughtdamage not reported0, 0NWS zone PAZ014 (BUTLER), zone-levelB1-c worst recorded: Drought
1997-11-13Ice Storm$5,000 property; crops not reported (zone total, 1997 dollars)0, 0NWS zone PAZ014 (BUTLER), zone-levelB1-c worst recorded: Ice Storm
1996-06-19Lightning$10,000 property; crops not reported (1996 dollars)0, 0MARSB1-c worst recorded: Lightning
1985-05-31TornadoF3, 22 mi path length (whole path, pre-1996), 243 yd wide$25,000,000 property; crops not recorded (1985 dollars)6, 80location not recordeddeaths or injuries recorded

The full list is in the Excel file, sheet "B1-d Storm Events history" (1,073 rows).

Location is the place NOAA recorded, as written in its data; it need not be a jurisdiction in this plan.

Local data needed: state-declared emergencies, from your state emergency management agency (federal data do not include them).

FEMA's declaration data list no tribal or special-area declarations for this state.

Supports FEMA checklist item B1-e: probability of future events

Probability: FEMA annualized frequency and descriptor per hazard

Sources: 5, 6

HazardFEMA annualized frequency (modeled)unit per rowUnitIn plain termsDescriptorDescriptor basisNRI events or days in its record period (hail, wind and tornado are area-weighted, so can be fractional)NRI periodLocationNote
Cold Wave3.26event-days per yearabout 3.26 days per yearLikelyStorm Events event-days in 7 of 30 years, 1996 to 2025 (23.3%)622005-11-12 to 2024-11-12 (19 years)countywide
Drought0event-days per yearnone modeledPossibleStorm Events event-days in 1 of 30 years, 1996 to 2025 (3.33%)02000 to 2025 (25.25 years; D3 and D4 only)countywideNRI models no drought event-days here (2000 to 2025, 25.25 years; D3 and D4 only); Storm Events has a record in 1 of 30 years. The descriptor comes from Storm Events, which counts D2 drought that NRI leaves out.
Earthquake0.000558annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.0558%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail3.3events per yearabout 3.3 per yearHighly likelyFEMA annualized frequency (modeled)125.6 (modeled)1986 to 2023 (38 years)countywide
Heat Wave1.58event-days per yearabout 1.58 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)312005-11-12 to 2024-11-12 (19 years)countywideNo Storm Events heat wave record, 1996 to 2025
Hurricane0.0209events per yearabout 1 in 48 yearsPossibleFEMA annualized frequency (modeled)61851 to 2024 (Atlantic)see B1-fNRI counts hurricane and tropical storm tracks passing within storm-force wind range; federal declarations are in B1-d.
Ice Storm0.373event-days per yearabout 0.373 days per yearLikelyStorm Events event-days in 8 of 30 years, 1996 to 2025 (26.7%)261946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding2.46event-days per yearabout 2.46 days per yearLikelyStorm Events event-days in 24 of 30 years, 1996 to 2025 (80%)691996 to 2023 (28 years)see B1-f
Landslide1.01events per year (modeled)about 1.01 per yearHighly likelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning40.4days per year with a strikeabout 40.4 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind2.39events per yearabout 2.39 per yearHighly likelyFEMA annualized frequency (modeled)911986 to 2023 (38 years)countywide
Tornado0.332events per yearabout 1 in 3 yearsLikelyFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Wildfire0.0000284annual probability at a locationchance a given location in the county burns in a year: 0.00284%Storm Events records in 0 of 30 years, 1996 to 2025 (0%)not shownmodeledsee B1-fNo descriptor: no Storm Events record 1996 to 2025
Winter Weather13.4event-days per yearabout 13.4 days per yearLikelyStorm Events event-days in 24 of 30 years, 1996 to 2025 (80%)2542005-11-12 to 2024-11-12 (19 years)countywide

FEMA annualized frequency (modeled) is the National Risk Index v1.20 (December 2025) estimate of how often a hazard affects this county in a year; it is not recorded events divided by years, and its unit differs by hazard (events, event-days, or days with a lightning strike per year). For earthquake, wildfire, coastal flooding and tsunami the value is the chance (or number of events) at a location in the county, not across the county, so no "1 in N years" is given and the descriptor comes from Storm Events where it has a record (none for earthquake). The Methods page gives each hazard's method, from FEMA's National Risk Index Technical Documentation v1.20.

Where NRI gives event-days, the descriptor comes from the share of years with a Storm Events record; NRI's source records more events, so the two differ.

Descriptor scale used in this packet (defined per unit)

Sources: 5, 6

UnitDescriptorDefinition
events per yearHighly likely1 or more per year
events per yearLikelyabout once in 1 to 10 years
events per yearPossibleabout once in 10 to 100 years
events per yearUnlikelyless than once in 100 years
annual probabilityLikely10% to under 100% chance in a given year
annual probabilityPossible1% to under 10% chance in a given year
annual probabilityUnlikelyunder 1% chance in a given year
event-days (share of years)Highly likelyevent-days recorded in 90% or more of years
event-days (share of years)Likelyevent-days recorded in 10% to under 90% of years
event-days (share of years)Possibleevent-days recorded in some years but under 10% of years
lightning strike-daysHighly likelycloud-to-ground strikes on 1 or more days per year

Intensity bands: historical frequency (Storm Events)

Source: 6

HazardBandYearsEventscounty-coded recordsYears in periodEvents per yearevents / years
Hail1.00-1.99 in1996 to 202593303.1
Hail2.00 in+1996 to 20254300.133
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 20253553011.8
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 202515300.5
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 202568302.27
TornadoEF0-11996 to 202514300.467
TornadoEF2-31996 to 20250300
TornadoEF4-51996 to 20250300
Tornadounrated (EFU)1996 to 20250300

The bands show how often events of each severity were recorded in this county, to profile how severe events have been (FEMA's probability item asks for the range of intensities).

Hail smaller than 1 inch is not counted: on 2010-01-05 the National Weather Service raised its severe-hail threshold from 3/4 inch to 1 inch, so smaller reports became less common after 2009 (NWS Service Change Notice 09-52). NRI hail frequency uses a 0.75 inch threshold.

Optional: future conditions. Not a required item in the 2025 FEMA Local Mitigation Planning Policy Guide; some states ask for it. The federal Climate Mapping for Resilience and Adaptation (CMRA) site gives county exposure to future climate conditions (https://resilience.climate.gov/).

Supports FEMA checklist item B1-f: hazards that vary across jurisdictions

Range of census tract risk within the county

Source: 5

HazardTractsrated of allNRI risk score, 0 to 100Tracts by rating
MinMedianMax
Cold Wave47 of 4717.119.621.8Relatively Low 28, Very Low 19
Drought0 of 47No Rating 47
Earthquake47 of 470.820.546.6Relatively Low 1, Very Low 46
Hail47 of 475.330.543.1Relatively Low 9, Very Low 38
Heat Wave47 of 473.36.914.4Very Low 47
Hurricane47 of 4718.143.849.8Very Low 47
Ice Storm47 of 4710.227.950.3Relatively Low 16, Very Low 31
Inland Flooding47 of 470.360.596.4Very High 1, Relatively High 8, Relatively Moderate 25, Relatively Low 12, Very Low 1
Landslide47 of 4724.383.696.4Relatively Moderate 3, Relatively Low 22, Very Low 22
Lightning47 of 4747.577.992.7Relatively High 23, Relatively Moderate 23, Relatively Low 1
Strong Wind47 of 4730.465.982.5Relatively High 1, Relatively Moderate 37, Relatively Low 9
Tornado47 of 4714.640.954.4Relatively Moderate 1, Relatively Low 43, Very Low 3
Wildfire47 of 4721.959.472.2Relatively Low 5, Very Low 42
Winter Weather47 of 4720.250.368.0Relatively Moderate 28, Relatively Low 19

Rated tracts only: No Rating (score 0.0), Not Applicable and Insufficient Data tracts are counted but not used for the minimum, median and maximum.

The score ranks a tract against all U.S. tracts (100 = highest). The rating is FEMA's category for the tract's risk value, computed differently, so the two can disagree.

Frequency data for cold wave, hail, heat wave, ice storm, lightning, strong wind and winter weather are county-wide or coarse (49 km grid or NWS zone), the same for every jurisdiction; the tract range mostly reflects where buildings and people are.

Each jurisdiction (starting figures from federal data)

Sources: 1, 3, 4, 6

JurisdictionTypePlan statusRepetitive lossFMA RL and SRL (44 CFR 77.2); repeat-flood, any definitionPublic Assistance to this jurisdictionFEMA records matched by applicant name; federal share obligated, nominal dollarsEvent records naming this placeall years; since its planNotes
Bruin boroughOrganized BoroughNo approved plan on recordFMA RL 0, SRL 0; any 0no Public Assistance recorded9 total; no approved plan
Butler cityCityApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$63,947.4059 total; 3 since its plan
Callery boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0no Public Assistance recorded5 total; 4 since its plan
Cherry Valley boroughOrganized BoroughNo approved plan on recordFMA RL 0, SRL 0; any 0no Public Assistance recorded0 total; no approved plan
Chicora boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 1no Public Assistance recorded13 total; no approved plan
Connoquenessing boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$2,262.650 total; 0 since its plan
East Butler boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$2,058.796 total; 1 since its plan
Eau Claire boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0no Public Assistance recorded9 total; no approved plan
Evans City boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 3, SRL 3; any 12$138,221.1233 total; 5 since its plan
Fairview boroughOrganized BoroughNo approved plan on recordFMA RL 0, SRL 0; any 0$1,045.711 total; no approved plan
Harmony boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 0; any 6$46,040.5820 total; 6 since its plan
Harrisville boroughOrganized BoroughNo approved plan on recordFMA RL 0, SRL 0; any 0no Public Assistance recorded10 total; no approved plan
Karns City boroughOrganized BoroughNo approved plan on recordFMA RL 0, SRL 0; any 0no Public Assistance recorded6 total; no approved plan
Mars boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0$10,276.2835 total; no approved plan
Petrolia boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0no Public Assistance recorded7 total; no approved plan
Portersville boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0$2,20517 total; no approved plan
Prospect boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0no Public Assistance recorded13 total; no approved plan
Saxonburg boroughOrganized BoroughPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0$7,106.3821 total; no approved plan
Seven Fields boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$8,449.650 total; 0 since its plan
Slippery Rock boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$2,499.5740 total; 8 since its plan
Valencia boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$916.506 total; 1 since its plan
West Liberty boroughOrganized BoroughNo approved plan on recordFMA RL 0, SRL 0; any 0$2,160.429 total; no approved plan
West Sunbury boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0no Public Assistance recorded5 total; 0 since its plan
Zelienople boroughOrganized BoroughApproved, expires 2026-11-22FMA RL 0, SRL 3; any 7$238,799.3041 total; 7 since its plan
Adams townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$66,771.720 total; 0 since its plan
Allegheny townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0no Public Assistance recorded0 total; no approved plan
Brady townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0$7,689.050 total; no approved plan
Buffalo townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 3$610,338.430 total; 0 since its plan
Butler townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$33,107.1359 total; 3 since its plan
Center townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 1; any 1$34,086.670 total; 0 since its plan
Cherry townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$17,450.680 total; 0 since its plan
Clay townshipTownshipNo approved plan on recordFMA RL 0, SRL 0; any 0$30,225.780 total; no approved plan
Clearfield townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$48,636.060 total; 0 since its plan
Clinton townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 1$55,004.102 total; 0 since its plan
Concord townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$41,351.070 total; 0 since its plan
Connoquenessing townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$50,865.830 total; 0 since its plan
Cranberry townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$256,034.220 total; 0 since its planIncludes $123,981.87 for declarations not counted as hazard incidents (DR-4506-PA).
Donegal townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$7,340.690 total; 0 since its plan
Fairview townshipTownshipNo approved plan on recordFMA RL 0, SRL 0; any 0$7,795.281 total; no approved plan
Forward townshipTownshipApproved, expires 2026-11-22FMA RL 5, SRL 9; any 17$18,309.080 total; 0 since its plan
Franklin townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$11,947.780 total; 0 since its plan
Jackson townshipTownshipApproved, expires 2026-11-22FMA RL 4, SRL 6; any 16$73,791.990 total; 0 since its plan
Jefferson townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 1$8,067.980 total; no approved plan
Lancaster townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 1$6,498.110 total; 0 since its plan
Marion townshipTownshipNo approved plan on recordFMA RL 0, SRL 1; any 1$5,068.870 total; no approved plan
Mercer townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 1no Public Assistance recorded0 total; 0 since its plan
Middlesex townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 1$117,094.660 total; no approved plan
Muddy Creek townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$6,801.999 total; 8 since its plan
Oakland townshipTownshipNo approved plan on recordFMA RL 0, SRL 0; any 0$7,477.760 total; no approved plan
Parker townshipTownshipNo approved plan on recordFMA RL 0, SRL 0; any 0$3,500.540 total; no approved plan
Penn townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 9$73,920.870 total; 0 since its plan
Slippery Rock townshipTownshipApproved, expires 2026-11-22FMA RL 1, SRL 1; any 4$5,430.2640 total; 8 since its plan
Summit townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 1; any 1$19,889.320 total; 0 since its plan
Venango townshipTownshipNo approved plan on recordFMA RL 0, SRL 0; any 0$11,195.070 total; no approved plan
Washington townshipTownshipApproved, expires 2026-11-22FMA RL 0, SRL 0; any 0$3,041.690 total; 0 since its plan
Winfield townshipTownshipPlan 107760 approved 2021-11-23, pending adoption here; not yet eligibleFMA RL 1, SRL 0; any 2$33,871.510 total; no approved plan
Worth townshipTownshipApproved, expires 2026-11-22FMA RL 3, SRL 1; any 7$10,392.680 total; 0 since its plan

Repetitive-loss counts are for whole NFIP communities, which can extend beyond this county (see the note in B2-c).

County Public Assistance in B1-d also includes applicants filed under the county that are not jurisdictions in this plan (for example state agencies, special districts and nonprofits), so the jurisdiction rows add up to less.

Supports FEMA checklist items B2-a and B2-b: vulnerability and potential impacts

Local data needed

The table below gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.

No county-level plan row in FEMA data, so there is no approval date to count from.

  • Critical facilities and lifelines per hazard
  • A problem statement per jurisdiction per hazard
  • Changes in development in hazard-prone areas since the last approval, or a statement of none (E1-a)
  • Future assets

County-level starter: exposure, expected annual loss and damage since the plan

Sources: 1, 2, 3, 5, 6, 7

HazardBuilding exposuremodeled dollarsAgriculture exposuremodeled dollarsPopulation exposedpeopleEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL as % of exposurebuildings; agriculture where notedStorm Events damage since plancounty-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Cold Wave$50,973,276,095$63,780,251193,593$1,790$16,705$168,367under 0.0001%
Droughtn/a$0n/an/a$0n/aagriculture exposure is 0 in NRI
Earthquake$85,620,204,390n/a193,763$293,077n/a$66,0350.000342%
Hail$50,973,276,095$63,780,251193,593$89,138$1,467$24,9090.000175%
Heat Wave$50,973,276,095$63,780,251193,593under $1$2,311$282,952under 0.0001%
Hurricane$50,964,703,735$63,417,834193,519$148,077$21,175$6,1270.000291%
Ice Storm$50,973,276,095n/a193,593$24,078n/a$88,707under 0.0001%
Inland Flooding$50,931,027,986$726,7643,336$41,153,132$12,496$136,696n/a (see note)NRI counts the full building value of any census block with some flood loss; this is not the value of buildings in the floodplain. Use local FIRM overlays for B2-a/B2-b.
Landslide$3,724,101,092n/a15,796$11,350n/a$19,1630.000305%
Lightning$50,973,276,095n/a193,593$12,903n/a$1,380,784under 0.0001%
Strong Wind$50,973,276,095$63,780,251193,593$533,888$1,277$989,4530.00105%
Tornado$50,973,276,095$63,780,251193,593$1,450,962$1,761$602,4190.00285%
Wildfire$19,126,209,858$21,185,04675,497$25,350$5$3,0650.000133%
Winter Weather$50,973,276,095$63,780,251193,593$107,080$25$31,7290.00021%

Totals since the plan: not available. No county-level plan row in FEMA data, so there is no approval date to count from.

FEMA does not split Public Assistance by hazard. A declaration mapped to several hazards is listed under each of them with its full amount, so the per-hazard column does not add up to the total; the unit total counts each declaration once.

NRI computes earthquake exposure on its own basis, so it exceeds the county building value in B2-a.

Supports FEMA checklist item B2-a: vulnerability (county context)

County context

Source: 5

MeasureValue
Population193,593
Building value (total, not at risk)$50,973,276,095
Agriculture value (total, not at risk)$63,780,251
NRI risk rating (all hazards)Relatively Low
Expected annual loss, buildings and agriculture, all hazards$43,908,048
Expected annual loss, population equivalence, all hazards (NRI values each statistical life at $13.7M; a modeled value of expected deaths and injuries, not property damage)$3,800,405
Social vulnerability ratingRelatively Low
Community resilience ratingVery High
NRI versionDecember 2025

FEMA's all-hazard expected annual loss adds buildings, agriculture and population equivalence; this table gives the property part and the population-equivalence part as separate rows.

Social vulnerability: higher means people are more likely to be harmed and slower to recover. Community resilience: lower means the community is less able to recover. High social vulnerability and low resilience both raise the NRI risk rating.

Supports FEMA checklist item B2-c: repetitive loss properties

Repetitive loss in this county, both definitions

Sources: 1, 4

DefinitionPropertiesSevere repetitive lossProperties
Repetitive loss, FMA definition (44 CFR 77.2)17Severe repetitive loss, FMA definition (44 CFR 77.2)26
Repetitive loss, NFIP insurance definition89Severe repetitive loss, NFIP insurance definition22

The state NFIP coordinator's list, the source FEMA's Handbook names, often uses the NFIP insurance definition (second row).

Repeat-flood properties: county and state-level rows

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total1726892295229
of which: Butler City of (community ID not in plan data)0030302
of which: Chicora borough0010100
of which: Evans City borough331231204
of which: Harmony borough0060601
of which: Marion township0111100
of which: Slippery Rock township1131402
of which: Zelienople borough0373702
of which: Winfield township1020200
of which: Middlesex township0010100
of which: Penn township0090903
of which: Buffalo township0030301
of which: Center township0100110
of which: Forward township591471713
of which: Jackson township461661603
of which: Jefferson township0010101
of which: Lancaster township0010101
of which: Worth township3160705
of which: Clinton township0010101
of which: Mercer township0010100
of which: Summit township0111100
Statewide, no county in FEMA's file0010100

The statewide row counts properties FEMA's file gives with no county in this state; they are listed for reference and are not in this county's counts.

Repeat-flood properties by jurisdiction in the plan (NFIP community)

Sources: 1, 4

JurisdictionNFIP community IDRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredpropertiesNote
Bruin borough4202110000000
Butler city4211380000000shared NFIP community; count covers the joint community
Callery borough4202130000000
Cherry Valley borough4226820000000
Chicora borough4202140010100
Connoquenessing borough4214130000000
East Butler borough4202150000000
Eau Claire borough4223480000000
Evans City borough420216331231204
Fairview borough4226850000000
Harmony borough4202170060601
Harrisville borough4223510000000
Karns City borough4202180000000
Mars borough4202200000000
Petrolia borough4202210000000
Portersville borough4223550000000
Prospect borough4223560000000
Saxonburg borough4223570000000
Seven Fields borough4226830000000
Slippery Rock borough4214140000000
Valencia borough4202230000000
West Liberty borough4202250000000
West Sunbury borough4226840000000
Zelienople borough4202260373702
Adams township4214150000000
Allegheny township4223410000000
Brady township4222410000000
Buffalo township4214160030301
Butler township4211380000000shared NFIP community; count covers the joint community
Center township4214170100110
Cherry township4223420000000
Clay township4223430000000
Clearfield township4223440000000
Clinton township4223450010101
Concord township4223460000000
Connoquenessing township4214180000000
Cranberry township4212170000000
Donegal township4223470000000
Fairview township4226030000000
Forward township421419591471713
Franklin township4223500000000
Jackson township421420461661603
Jefferson township4214210010101
Lancaster township4214220010101
Marion township4202190111100
Mercer township4223520010100
Middlesex township4212290010100
Muddy Creek township4223530000000
Oakland township4223540000000
Parker township4212190000000
Penn township4212410090903
Slippery Rock township4202221131402
Summit township4223580111100
Venango township4223590000000
Washington township4202240000000
Winfield township4212251020200
Worth township4214253160705

Counts by occupancy group for each jurisdiction are in the Excel file, sheet "B2-c Jurisdictions".

Jurisdiction rows are whole NFIP communities and need not add up to the county total: a community that extends into another county is counted in full on each jurisdiction row, while the county table counts only its part in this county.

County repeat-flood properties by occupancy group

Sources: 1, 4

Occupancy groupRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
single-family residential1726792285226
2 to 4 unit residential0010101
other residential0000000
non-residential0090902
not reported0000000

FEMA's occupancy groups have no institutional class; institutional properties are counted in non-residential or other residential in the table by occupancy group.

FMA RL and FMA SRL are the Flood Mitigation Assistance definitions (44 CFR 77.2), the ones the FEMA Local Mitigation Planning Policy Guide cites. NFIP repetitive loss (the FEMA insurance definition) is 2 or more claims over $1,000 in 10 years, and a property can leave that group once it is mitigated. Also shown: NFIP severe repetitive loss, any category, mitigated and currently insured. The Methods page gives the OpenFEMA field details.

Counts are aggregates of FEMA's public NFIP Multiple Loss Properties file (FEMA's data date 2026-08-02; file version 2026-08-04). No property is identified. County assignment is FEMA's geocode.

In this county 4 properties are FMA repetitive loss but not NFIP repetitive loss, and 76 properties are NFIP repetitive loss but not FMA repetitive loss.

Exact counts; no count suppression.

Sources

Tables cite these sources by number. The full list, for the plan's bibliography (FEMA review item A4-a):

  1. FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-29T134039Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
  2. FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-29T162832Z, pulled 2026-09-30, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
  3. FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-29T150754Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
  4. FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
  5. FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-30, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
  6. NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-30, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
  7. NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-30, https://www.weather.gov/gis/ZoneCounty
  8. U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-30, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_counties_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_cousubs_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_place_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_unsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_elsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_scsd_national.zip, https://www2.census.gov/geo/docs/reference/codes2020/national_place_by_county2020.txt, https://www2.census.gov/geo/docs/reference/ct_change/ct_cou_to_cousub_crosswalk.xlsx (used to match place names and codes; no table prints its values)

What this packet is and what the plan adds

This packet is the federal data for the plan's risk assessment (the summary on page 1 says how it is organized); the plan and FEMA's review decide whether each item is met.

The plan adds what only the community has: local data on assets, critical facilities, development and each jurisdiction's impacts; local hazard history, including state-declared emergencies; the mitigation strategy; and adoption.

How the federal data are built: National Risk Index values are FEMA's model, not counts of events. Storm Events is more complete from 1996; zone-level records are placed by forecast zone, not by location in the county. Public Assistance for a jurisdiction is matched by applicant name. The Methods page gives every rule and the known edge cases.

OpenFEMA disclaimer

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

Reuse, citation and corrections

Reuse and citation: Hazard Plain text and tables are licensed under Creative Commons Attribution 4.0 International (CC BY 4.0, https://creativecommons.org/licenses/by/4.0/); credit Hazard Plain and the release. The underlying federal data are public domain; OpenFEMA data are also subject to the OpenFEMA terms and conditions.

Cite this: Hazard Plain (2026). Butler County, PA: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 42019). Automated baseline. https://hazardplain.org/pa/42019/ Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.

Corrections: to report an error, name the packet, the table and what your records show. Contact: contact@hazardplain.org