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Allegheny County, Pennsylvania

Natural disaster risk, federal disaster history and flood insurance facts.

Relatively High overall risk
2nd of 67highest risk in Pennsylvania
$354Mexpected losses a year
16federal declarations
1 in 250homes with flood insurance
Photo: High Contrast, CC BY 3.0

Allegheny County, Pennsylvania has a relatively high overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 98% of US counties. It ranks 2nd of 67 counties in Pennsylvania. The costliest hazards here are inland flooding, cold waves and tornadoes. FEMA estimates about $354 million a year in expected losses, or roughly $283 per resident. Since 1972 it has been included in 16 federal disaster or emergency declarations for natural events (12 major disasters). The most recent was in October 2013 (severe storms, tornadoes and flooding). Fewer than 1 in 100 homes here carry federal flood insurance (1,851 policies). Since 1978, federal flood insurance has paid about $81 million on 4,832 claims here, including $36 million for floods in 2004.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Allegheny County

$295 million a yearExpected losses. Damaging events about 7 times a year.
  • Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
  • Price a flood policy now. Most new federal policies take 30 days to start.

Cold wave

Very High
$31.9 million a yearExpected losses. Damaging events about 3 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.
$8.4 million a yearExpected losses. Damaging events about once every 4 years.
  • Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
  • Turn on emergency alerts on your phone and keep a weather radio.
HazardRatingScoreExpected loss a year
Inland floodingVery High99.2
$295M
Cold waveVery High98.8
$32M
TornadoHigh91.2
$8M
Heat waveModerate94.3
$5M
EarthquakeLow87.9
$4M
Strong windHigh96.3
$4M
Ice stormVery High96.1
$2M
LightningHigh93.7
$2M
HurricaneLow75.9
$1M
Winter weatherHigh93.3
$586K
HailVery Low31.3
$135K
WildfireVery Low60.4
$91K
LandslideLow87.2
$42K
AvalancheVery Low28.1
$94

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is relatively low and community resilience is very high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Allegheny County. 2020s bar runs to November 2026.

By type

Flood5
Severe Storm4
Snowstorm3
Hurricane3
Tornado1

Most recent

Oct 1, 2013Severe Storms, Tornadoes, and FloodingMajor disaster
Oct 29, 2012Hurricane SandyEmergency
Apr 16, 2010Severe Winter Storms and SnowstormsMajor disaster
Sep 10, 2005Hurricane KatrinaEmergency
Sep 19, 2004Severe Storms and Flooding Associated With Tropical Depression FrancesMajor disaster
Sep 19, 2004Tropical Depression IvanMajor disaster
Jun 8, 1998Severe Storms, Tornadoes,And FloodingMajor disaster
Jan 21, 1996Severe Storms and FloodingMajor disaster
Jan 13, 1996Blizzard of 96Major disaster
Mar 10, 1994Severe Winter StormsMajor disaster
Show all 16
Mar 16, 1993Severe Snowfall & Winter StormEmergency
Jun 5, 1986Severe Storms & FloodingMajor disaster
Nov 9, 1985Severe Storms & FloodingMajor disaster
Aug 27, 1984Severe Storms & FloodingMajor disaster
Jun 13, 1980Severe Storms & TornadoesEmergency
Jun 23, 1972Tropical Storm AgnesMajor disaster

Pennsylvania also had 7 statewide declarations that did not name single counties.

Storm history since 1954

Tornado risk by county ›

The National Weather Service has logged 2,379 storm reports in Allegheny County since 1954, with 10 deaths and 224 injuries and about $424 million in reported damage. The strongest on record here was an F4 tornado on June 3, 1980.

27tornadoes
445hail reports, largest 2.5 inches
1,262damaging thunderstorm winds
603floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Jun 3, 1980F4–20 / 0
Aug 3, 1963F3–70 / 2
May 22, 1983F2–0 / 0
May 13, 1956F2–5 / 0
Jun 2, 1998F1Carnegie50 / 0

Most damaging storms

DateTypeNearDamage
Jun 3, 1980Tornado–$250M
Jun 30, 1998Thunderstorm WindCountywide$41M
Aug 3, 1963Tornado–$25M
Aug 9, 2007Flash FloodMillvale$15M
Jun 2, 1998TornadoCarnegie$13M
Jun 20, 2018Flash FloodBoyce$10M

Source: NOAA Storm Events Database, county-based reports through Jul 18, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

Hurricanes and tropical storms

Hurricane risk by county ›

Since 1888, 0 hurricanes and 2 tropical storms have passed within 65 miles of the center of Allegheny County, 1 of them since 1950. The strongest was an unnamed storm in 1888, with top winds near 50 mph about 53 miles away.

0hurricanes
0major hurricanes (Category 3+)
2tropical storms
1979most recent: Frederic

Strongest storms nearby

DateStormStrengthClosest
Aug 21, 1888UnnamedTropical storm, 50 mph53 mi
Sep 14, 1979FredericTropical storm, 40 mph34 mi

Most recent storms

DateStormStrengthClosest
Sep 14, 1979FredericTropical storm, 40 mph34 mi
Aug 21, 1888UnnamedTropical storm, 50 mph53 mi

Source: NOAA National Hurricane Center best-track records (HURDAT2), 1851 to 2025 for the Atlantic and 1949 to 2025 for the eastern Pacific. A storm counts if its track passed within 65 miles of the county's center while it was a tropical storm or hurricane. Strength is the storm's top sustained wind at that point, not the wind measured in the county. Older storms over the open sea were sometimes missed.

Flood insurance in Allegheny County

Check your address flood zone ›
0.4%of homes have federal flood insurance (1,851 policies)
27.9%of homes in mapped high-risk flood zones are insured
$81.4 millionpaid on 4,832 flood claims since 1978
2004costliest year, with $35.7 million paid

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Homes in Allegheny County

$227,600median home value (Pennsylvania $254,500, US $332,700)
1957median year homes were built (Pennsylvania 1965, US 1980)
77%of homes built before 1980, before many modern wind, quake and flood building rules
0.7%of homes are mobile homes, which are the least safe in tornadoes and high winds

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 606,827 housing units.

Compare in Pennsylvania

All 67 ›
Largest countiesOverall riskTop hazard
Philadelphia CountyVery HighInland flooding
Allegheny CountyHighInland flooding
Montgomery CountyHighInland flooding
Bucks CountyHighInland flooding
Delaware CountyModerateInland flooding
Lancaster CountyHighInland flooding
Chester CountyModerateInland flooding
York CountyModerateInland flooding

Neighboring counties

CountyOverall riskDeclarations
Westmoreland CountyModerate18
Washington CountyModerate12
Butler CountyLow9
Beaver CountyLow13

Common questions about Allegheny County

What is the biggest natural hazard in Allegheny County?

Inland flooding has the highest expected yearly losses in Allegheny County, about $295 million a year in FEMA's estimate. Cold wave is second at $31.9 million.

How many federal disasters has Allegheny County had?

Allegheny County has been included in 16 federal disaster or emergency declarations for natural events since 1972, including 12 major disasters. The most recent was Severe Storms, Tornadoes, and Flooding in October 2013.

Is Allegheny County a high-risk place to live?

Its overall rating is Relatively High, 2nd highest of 67 in Pennsylvania. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.

Do I need flood insurance in Allegheny County?

Standard home insurance does not cover flooding. About 1 in 250 homes in Allegheny County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.

How many tornadoes has Allegheny County had?

NOAA records list 27 tornadoes in Allegheny County since 1950. The strongest was an F4 tornado on June 3, 1980. The weather service has also logged 445 hail reports and 603 floods here.

How many hurricanes have hit Allegheny County?

NOAA's hurricane records show 0 hurricanes and 2 tropical storms passing within 65 miles of the center of Allegheny County. The strongest was an unnamed storm in 1888, with winds near 50 mph.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.