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Allegheny County, Pennsylvania severe weather history spans 2,357 recorded events between 1954 and 2026. The dominant hazard is thunderstorm wind, accounting for 52.9% of all recorded events. It ranks #9 nationally and #1 in Pennsylvania.
2,357
Recorded events
9
Direct deaths
223
Direct injuries
$423.3M
Property damage
The record
What the Allegheny County, Pennsylvania severe weather history record shows
Across the archive, Allegheny County, Pennsylvania severe weather history averages 32.7 recorded events a year. The busiest stretch on record is the 2010s, with 878 events logged in that decade alone. Roughly 162 events fall before 1990 and 2,195 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The deadliest hazard in the Allegheny County, Pennsylvania record is flash flood, responsible for 6 direct deaths. The costliest is tornado, with $292.9M in reported property damage. In total, 8 distinct hazard types appear in this county archive, each listed with its own dated record below.
By hazard type
Every hazard type recorded in Allegheny County
| Hazard | Events | Deaths | Damage | Max | Span |
|---|---|---|---|---|---|
| Thunderstorm Wind | 1,248 | 1 | $69.0M | 91 | 1955–2026 |
| Flash Flood | 497 | 6 | $60.3M | 0 | 1996–2026 |
| Hail | 444 | 0 | $6K | 2.5 | 1962–2025 |
| Flood | 99 | 0 | $883K | 0 | 2007–2021 |
| Heavy Rain | 31 | 0 | $0 | 0 | 2007–2022 |
| Tornado | 27 | 2 | $292.9M | F4 | 1954–2024 |
| Lightning | 10 | 0 | $122K | 0 | 1996–2024 |
| Debris Flow | 1 | 0 | $0 | 0 | 2017–2017 |
Decade by decade
Allegheny County, Pennsylvania severe weather history by decade
Reporting practice changed over time — early decades are undercounted, not calmer.
Tornado tracks
Paths crossing this county
28 mapped tornado paths intersect this county: 25 touched down inside it and 3 crossed in from a neighbouring county. This comes from path geometry, not county-tagged reports.
| Date | Scale | Deaths | Injuries | Path length | Origin |
|---|---|---|---|---|---|
| 1980-06-03 | EF4 | 0 | 140 | 11.8 mi | Touched down here |
| 1963-08-03 | EF3 | 2 | 70 | 0.1 mi | Touched down here |
| 1983-05-22 | EF2 | 0 | 10 | 38.0 mi | Touched down here |
| 1975-06-04 | EF2 | 0 | 0 | 45.3 mi | Crossed in |
| 1956-05-13 | EF2 | 0 | 5 | 0.7 mi | Touched down here |
| 2024-05-17 | EF1 | 0 | 0 | 1.9 mi | Touched down here |
| 2024-05-07 | EF1 | 0 | 0 | 0.2 mi | Touched down here |
| 2024-06-26 | EF1 | 0 | 0 | 6.8 mi | Crossed in |
| 2024-06-26 | EF1 | 0 | 0 | 11.5 mi | Touched down here |
| 2021-10-21 | EF1 | 0 | 0 | 4.7 mi | Touched down here |
Significant events
Deadliest events on record in Allegheny County
| Date | Type | Location | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Aug 19, 2011 | Flash Flood | SHARPSBURG | 4 | 1 | $500K |
| Aug 4, 1963 | Tornado | 2 | 70 | $25.0M | |
| May 31, 2002 | Thunderstorm Wind | HOMESTEAD | 1 | 54 | $10.0M |
| Jul 1, 1997 | Flash Flood | PITCAIRN | 1 | 0 | $10.0M |
| Jun 20, 1996 | Flash Flood | LEETSDALE | 1 | 0 | $0 |
| Jun 2, 1998 | Tornado | CARNEGIE | 0 | 50 | $13.0M |
| Jun 3, 1980 | Tornado | 0 | 20 | $250.0M | |
| Jun 30, 1998 | Thunderstorm Wind | COUNTYWIDE | 0 | 10 | $41.0M |
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
A NWS storm survey found that 2.5 inches of rain fell in one hour in a very urbanized 4.8 sq mi watershed just east of downtown Pittsburgh. Severe flash flooding developed on Washington Blvd resulting in four fatalities and up to 15 water rescues. A mother and two daughters were drowned inside a van when it became submerged in approximately 9 ��� 10 feet of water. An elderly lady who abandoned her car was apparently swept or fell into an open manhole or catch basin and drowned.
A microburst with winds up to 85 MPH moved diagonally from northwest to southeast across Allegheny County, leaving a wide swath of damage in its wake. These winds produced an estimated $41 million in damage across the county. Over 125,000 people across the county had their power knocked out by this storm. Across the city of Pittsburgh, the North Hills area reported numerous trees, branches, and power lines down across an area one to two miles wide and nearly five miles in length. Many homes were damaged by falling trees and branches. The Larouche College area was especially hard hit with significant roof and window damage. The roof was torn from a McCandless convent, injuring three nuns.
Heavy rain caused flash flooding in the Millvale area and much of the North Hills area of Pittsburgh as Girtys Run came out of it's banks. Over 900 homes were affected by the flooding as well as over 200 businesses. Infrasturcture owned by local municipalities sustained over 4 million dollars in damage.
Context
Risk, population and federal disasters
Relatively High
FEMA NRI risk rating
1,238,177
Population (ACS)
$228K
Median home value
18
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| Mar 30, 2020 | Biological | COVID-19 PANDEMIC | DR |
| Mar 13, 2020 | Biological | COVID-19 | EM |
| Oct 1, 2013 | Severe Storm | SEVERE STORMS, TORNADOES, AND FLOODING | DR |
| Oct 29, 2012 | Hurricane | HURRICANE SANDY | EM |
| Apr 16, 2010 | Snowstorm | SEVERE WINTER STORMS AND SNOWSTORMS | DR |
| Sep 10, 2005 | Hurricane | HURRICANE KATRINA | EM |
Within the county
Most affected places
- Option 148
Quick answers
Frequently asked
How many severe weather events have been recorded in Allegheny County, Pennsylvania?
2,357 events are on record between 1954 and 2026, causing 9 direct deaths and $423.3M in property damage.
What is the most common severe weather hazard in Allegheny County?
Thunderstorm Wind, with 1,248 recorded events — 52.9% of everything in the archive for this county.
How many tornadoes have crossed Allegheny County?
28 mapped tornado paths intersect the county boundary; 25 of them touched down inside it. This is derived from path geometry, not county-tagged reports.
How many federal disaster declarations cover Allegheny County?
18 federal disaster declarations from FEMA include Allegheny County, each tied to a specific incident period.
How risky is Allegheny County compared with the rest of the country?
FEMA's National Risk Index rates Allegheny County as relatively high risk, placing it in the 98 percentile of its state for expected annual loss.
Where does the Allegheny County, Pennsylvania severe weather history data come from?
Every figure is drawn from United States federal public-domain records: NOAA/NCEI Storm Events for the event archive, NOAA SPC SVRGIS for mapped tornado paths, FEMA for disaster declarations and risk ratings, and the U.S. Census for population context. Dates are shown in UTC and recent entries may still be revised by NOAA.
Nearby
Neighbouring counties
- Adams County 397
- Armstrong County 510
- Beaver County 840
- Bedford County 267
- Berks County 1,349
- Blair County 304
Cite this page
“Allegheny County, Pennsylvania.” Severe Weather History. severeweatherhistory.com/county/pennsylvania/allegheny-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.