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Pennsylvania Environment & Hazard Risk

5 counties rated high or very high risk. 49,838 storm events since 1996, #14 among states.

Expected yearly loss
$4.07B
$313 per person
Storm events since 1996
49,838
Most often thunderstorm wind
Flood insurance policies
31,965
$1.43B in claims paid
Superfund sites
127
1,044 toxic release facilities

Risk by county

FEMA National Risk Index rating, highest risk first

CountyOverall riskTop hazardFlood policiesFlood claims paid
Philadelphia CountyVery HighHeat wave1,383$47.61M
Allegheny CountyHighCold wave1,851$81.56M
Montgomery CountyHighWinter weather2,284$185M
Lancaster CountyHighWinter weather678$32.8M
Bucks CountyHighWinter weather2,658$150M
Lehigh CountyModerateCold wave423$12.44M
Delaware CountyModerateWinter weather1,153$57.24M
Berks CountyModerateWinter weather684$23.61M
Chester CountyModerateDrought1,015$37.56M
Luzerne CountyModerateWinter weather3,881$93.95M
Dauphin CountyModerateWinter weather1,130$86.09M
York CountyModerateWinter weather674$20.71M
Northampton CountyModerateWinter weather594$48.39M
Lackawanna CountyModerateWinter weather878$20.54M
Westmoreland CountyModerateLightning752$21.57M
Cumberland CountyModerateWinter weather555$16.91M
Schuylkill CountyModerateWinter weather596$26.28M
Monroe CountyModerateLightning356$14.76M
Erie CountyModerateLightning290$5.97M
Washington CountyModerateLandslide468$21.07M
Fayette CountyModerateLandslide208$10.09M
Lebanon CountyLowWinter weather221$15.94M
Lycoming CountyLowWinter weather661$58.33M
Butler CountyLowLightning326$15.41M
Northumberland CountyLowWinter weather365$24.25M
Mercer CountyLowLightning62$880K
Blair CountyLowWinter weather500$8.53M
Cambria CountyLowLightning357$3.24M
Franklin CountyLowHurricane213$1.08M
Crawford CountyLowWinter weather251$1.67M
Beaver CountyLowLandslide205$13.69M
Bradford CountyLowLightning458$24.79M
Armstrong CountyLowLandslide212$6.19M
Mifflin CountyLowWinter weather160$3.85M
Bedford CountyLowLandslide235$13.35M
Centre CountyLowWinter weather266$2.98M
Adams CountyLowDrought266$6.7M
Clearfield CountyLowWinter weather195$5.9M
Lawrence CountyLowLightning126$1.96M
Pike CountyLowHurricane172$2.96M
Warren CountyLowStrong wind154$1.09M
Somerset CountyLowLandslide257$2.59M
Indiana CountyLowLandslide171$2.35M
Columbia CountyLowWinter weather490$63.17M
Tioga CountyLowLandslide282$3.53M
Carbon CountyLowLightning152$451K
Jefferson CountyLowLightning117$7.73M
Wayne CountyLowHurricane152$4.72M
Venango CountyLowLightning92$5.9M
Union CountyLowStrong wind231$11.75M
Greene CountyLowLandslide87$3.51M
Snyder CountyLowWinter weather194$12.45M
McKean CountyLowWinter weather181$1M
Susquehanna CountyLowLandslide176$13.36M
Perry CountyLowLandslide180$7.44M
Clinton CountyLowStrong wind336$8.2M
Huntingdon CountyLowStrong wind234$8.83M
Elk CountyLowLightning82$8.29M
Wyoming CountyLowLandslide198$28.57M
Juniata CountyVery LowLandslide68$1.12M
Clarion CountyVery LowLightning37$2.93M
Potter CountyVery LowLandslide122$1.12M
Forest CountyVery LowLightning18$194K
Montour CountyVery LowHurricane62$3.19M
Cameron CountyVery LowLandslide57$532K
Sullivan CountyVery LowLandslide58$3.92M
Fulton CountyVery LowLandslide15$363K

Costliest hazards

Expected annual loss in Pennsylvania, all counties combined

  • Heat wave$365M/yr · 3 counties high
  • Cold wave$256M/yr · 11 counties high
  • Hurricane$170M/yr · 2 counties high
  • Tornado$153M/yr · 6 counties high
  • Earthquake$148M/yr · 1 county high
  • Strong wind$97.18M/yr · 20 counties high
  • Lightning$55.18M/yr · 31 counties high
  • Winter weather$33.22M/yr · 25 counties high
  • Drought$20.86M/yr · 2 counties high
  • Hail$14.91M/yr · 1 county high

Storm events by type

Since 1996: 815 deaths, $4.24B in property and crop damage

  • Thunderstorm Wind20,142 · 41 deaths
  • Flash Flood4,935 · 77 deaths
  • Hail4,647
  • Winter Weather3,470 · 56 deaths
  • Heavy Snow2,452 · 15 deaths
  • Winter Storm2,447 · 44 deaths
  • Flood2,207 · 33 deaths
  • High Wind1,628 · 26 deaths
  • Strong Wind1,259 · 14 deaths
  • Drought812
  • Heat711 · 318 deaths
  • Tornado614 · 7 deaths

Events per year

Storm events per year in Pennsylvania

Most damaging storms

Since 2017, ranked by deaths, injuries and damage

  • Winter Weather03/28/2022

    Schuylkill

    6 deaths, 24 injured

    What happened

    SNOW SQUALL. A snow squall passed over I-81 in Schuylkill County shortly after 10:30am (EDT) on March 28, 2022, causing an 80 vehicle pileup at mile marker 116 on the northbound lanes that resulted in 6 fatalities, an additional 24 injuries, and closed the northbound lanes between mile markers 107 and 119 for more than 24 hours. State Route 901 was also closed.

  • Flash Flood07/15/2023

    Buckmanville, Bucks County

    7 deaths

    What happened

    Catastrophic flash flooding occurred in Upper Makefield Township, resulting in the loss of seven lives. A reliable rain gauge located within the township indicated that 4.64 inches of rain fell during the event which lasted less than 2 hours. Widespread roadway flooding occurred with many roads becoming impassable. Numerous water rescues took place in the township. The worst of the flooding occurred along Hough's Creek. The creek rose rapidly and the rushing water carried away many vehicles, most along Taylorsville Road which parallels the Delaware Canal. Eleven vehicles were reported to have been swept into the creek. Eight individual were rescued from their vehicle and two from the creek. Unfortunately, seven people perished either while trapped in their vehicle or while attempting to escape the flood waters.||The Taylorsville Road Bridge over Hough's Creek was structurally compromised. PA Route 532 between Stonebridge Crossing Road and Wrightstown Road was damaged severely by the raging flood waters from Hough's Creek.

  • Flash Flood09/02/2021

    Wayne Jct, Philadelphia County

    $60M damage

    What happened

    Widespread flash flooding occurred in Philadelphia with many roadways closed. Most of the waterways in the city overflowed their banks, including the Schuylkill River, Cobbs Creek, Wissahickon Creek, Frankford Creek and Pennypack Creek. Many buildings were flooded, especially in the Manayunk section of the city.

  • Flash Flood09/01/2021

    Nottingham, Chester County

    1 death, $41M damage

    What happened

    Widespread flash flooding occurred in Chester County with many road closures and vehicles stranded. There was a flood related fatality in Downingtown. Numerous waterways in the county flooded, including the Schuylkill River, the West Branch of the Brandywine Creek, the East Branch of the Brandywine Creek, White Clay Creek, Red Clay Creek, French Creek and Valley Creek. There were many reports of water entering buildings and homes.

  • Flash Flood09/01/2021

    King of Prussia, Montgomery County

    2 deaths, $21M damage

    What happened

    Widespread flash flooding occurred in Montgomery County with many road closures and vehicles stranded. Numerous water rescues took place. There were two flood related fatalities, one in Skippack and one in Bridgeport. Many buildings and homes were flooded. Most waterways in the county overflowed their banks, including the Schuylkill River, Perkiomen Creek and Wissahickon Creek.

  • Flash Flood09/02/2021

    Byberry, Philadelphia County

    $40M damage

    What happened

    Widespread flash flooding occurred in Philadelphia with many roadways closed. Most of the waterways in the city overflowed their banks, including the Schuylkill River, Cobbs Creek, Wissahickon Creek, Frankford Creek and Pennypack Creek. Many buildings were flooded, especially in the Manayunk section of the city.

Hurricanes and tropical storms

Storms whose track crossed the state, newest first

Flood insurance

National Flood Insurance Program policies and claims

31,965 homes in Pennsylvania have flood insurance, about 0.7% of residential buildings. In high-risk flood zones, 21,245 of 92,246 homes (23%) are insured.

Flood claims paid per year in Pennsylvania
  • Tropical Storm Lee$302M · 7,848 claims
  • Tropical Storm Ivan$182M · 8,116 claims
  • Flooding$133M · 12,137 claims
  • Hurricane Ida$108M · 1,802 claims
  • Hurricane Floyd$54.28M · 1,754 claims
  • Hurricane Irene$39.81M · 1,474 claims

Drinking water

1,849 community water systems serve about 11,466,690 people

Since 2021, 500 systems reported 1,271 health-based violations. 238 systems had a violation of any kind still open at last report. These had the most:

  • Pithole Water AssociationServes 87 · Groundwater · Private33 health violations+103 monitoring or reporting
  • Parker Area Water AuthServes 900 · Surface water · Local government27 health violations+6 monitoring or reporting
  • Pinecrest Village MhpServes 195 · Groundwater (surface influenced) · Private22 health violations+382 monitoring or reporting
  • Icmsa RossiterServes 500 · Surface water · Local government21 health violations+13 monitoring or reporting
  • Clarendon Acres Water CoServes 280 · Groundwater · Private18 health violations+84 monitoring or reporting
  • Woodhaven Mobile Home ParkServes 350 · Surface water · Private17 health violations+267 monitoring or reporting
  • Blawnox Boro Water DeptServes 2,200 · Purchased surface water · Local government15 health violations+19 monitoring or reporting
  • Polk CenterServes 1,058 · Surface water · State15 health violations+96 monitoring or reporting

Select a county above to see every system that serves it.

Climate in the largest cities

1991-2020 normals from the nearest NOAA weather station

CityJuly highJan lowRainSnow
Philadelphia89°F28°F50.7 in16.1 in
Pittsburgh83°F22°F41.3 in-
Allentown86°F22°F47.4 in33.1 in
Reading87°F23°F45.2 in-
Erie81°F21°F43.0 in104.3 in
Scranton85°F20°F38.7 in45.1 in
Lancaster87°F22°F44.1 in21.4 in
Levittown86°F22°F50.7 in19.9 in

Pollution sites

127 Superfund sites and 1,044 toxic release facilities

Superfund sites

All 127 in Pennsylvania

Largest toxic releases

All 1,044 in Pennsylvania

Facilities in Pennsylvania reported 42.3 million lbs of toxic releases in 2024, 10.8 million lbs of it into the air.

Frequently asked questions

What is the biggest natural hazard in Pennsylvania?
By expected annual loss, heat wave costs the most in Pennsylvania ($365M a year), according to FEMA's National Risk Index.
How many storms hit Pennsylvania each year?
NOAA recorded 49,838 storm events in Pennsylvania since 1996, about 1,608 a year. The most common type is thunderstorm wind.
How many homes in Pennsylvania have flood insurance?
31,965 residential flood insurance policies are in force in Pennsylvania. Since 1978 the National Flood Insurance Program has paid $1.43B on 75,803 claims here.
How many Superfund sites are in Pennsylvania?
Pennsylvania has 127 Superfund sites on or deleted from EPA's National Priorities List.

Source: FEMA, NOAA, EPA · Last updated 08/01/2026 · Storm counts include events in forecast zones that touch each county. This product uses the FEMA OpenFEMA API, but is not endorsed by FEMA.