Allegheny County, Pennsylvania
Natural disaster risk, federal disaster history and flood insurance facts.
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
- 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.
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
- 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.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 99.2 | $295M | ||
| Cold wave | 98.8 | $32M | ||
| Tornado | 91.2 | $8M | ||
| Heat wave | 94.3 | $5M | ||
| Earthquake | 87.9 | $4M | ||
| Strong wind | 96.3 | $4M | ||
| Ice storm | 96.1 | $2M | ||
| Lightning | 93.7 | $2M | ||
| Hurricane | 75.9 | $1M | ||
| Winter weather | 93.3 | $586K | ||
| Hail | 31.3 | $135K | ||
| Wildfire | 60.4 | $91K | ||
| Landslide | 87.2 | $42K | ||
| Avalanche | 28.1 | $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
Most recent
Show all 16
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.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Jun 3, 1980 | F4 | – | 20 / 0 |
| Aug 3, 1963 | F3 | – | 70 / 2 |
| May 22, 1983 | F2 | – | 0 / 0 |
| May 13, 1956 | F2 | – | 5 / 0 |
| Jun 2, 1998 | F1 | Carnegie | 50 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Jun 3, 1980 | Tornado | – | $250M |
| Jun 30, 1998 | Thunderstorm Wind | Countywide | $41M |
| Aug 3, 1963 | Tornado | – | $25M |
| Aug 9, 2007 | Flash Flood | Millvale | $15M |
| Jun 2, 1998 | Tornado | Carnegie | $13M |
| Jun 20, 2018 | Flash Flood | Boyce | $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.
Strongest storms nearby
| Date | Storm | Strength | Closest |
|---|---|---|---|
| Aug 21, 1888 | Unnamed | Tropical storm, 50 mph | 53 mi |
| Sep 14, 1979 | Frederic | Tropical storm, 40 mph | 34 mi |
Most recent storms
| Date | Storm | Strength | Closest |
|---|---|---|---|
| Sep 14, 1979 | Frederic | Tropical storm, 40 mph | 34 mi |
| Aug 21, 1888 | Unnamed | Tropical storm, 50 mph | 53 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 ›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
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 counties | Overall risk | Top hazard |
|---|---|---|
| Philadelphia County | Inland flooding | |
| Allegheny County | Inland flooding | |
| Montgomery County | Inland flooding | |
| Bucks County | Inland flooding | |
| Delaware County | Inland flooding | |
| Lancaster County | Inland flooding | |
| Chester County | Inland flooding | |
| York County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Westmoreland County | 18 | |
| Washington County | 12 | |
| Butler County | 9 | |
| Beaver County | 13 |
Cities in Allegheny County
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.