4,832 flood insurance claims·$81.2M paid·6 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Allegheny County, Pennsylvania. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Flash flooding from summer thunderstorms dominates the flood risk profile in Allegheny County, accounting for 496 events and 6 deaths over the last 30 years compared to 125 general flood events and 1 death.
Recent weather patterns illustrate this severe thunderstorm threat. On May 21, 2025, an occluding surface low and embedded thunderstorms produced multiple rounds of slow-moving heavier rain that caused flash flooding incidents. Later that season, on June 14, 2025, a near-stationary boundary and high precipitable water values supported slow-moving thunderstorms that dumped 2 to 3 inches of rain in an hour, resulting in stranded vehicles and water entering homes.
Homeowners, real estate agents, and journalists should note that flood risk extends beyond designated high-risk areas. While FEMA National Flood Insurance Program records show significant impacts in high-risk Zone A with 2,875 claims (averaging $22,605 and 12 inches of recorded water depth), properties in moderate-to-low risk Zone X also face substantial hazards, registering 953 claims with an average payout of $25,682 and an average recorded water depth of 10 inches. Additional claims are recorded across Shaded Zone X (298 claims, average 8-inch depth) and Unshaded Zone X (252 claims, average 6-inch depth).
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
16% of Allegheny County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
3,429 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 10 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2004, with 1,221 claims and $35.5M paid, the year of Severe Storms and Flooding Associated With Tropical Depression Frances and Tropical Depression Ivan.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
379 NOAA storm reports from Allegheny County describe what happened, in the words of the forecasters who covered it. Read the Pennsylvania flood stories →
18 federal disaster declarations since 1972, 6 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Tornadoes, And Flooding | Jun 26, 2013 |
| Hurricane Sandy | Oct 26, 2012 |
| Severe Winter Storms And Snowstorms | Feb 5, 2010 |
| Hurricane Katrina | Aug 29, 2005 |
| Tropical Depression Ivan | Sep 17, 2004 |
| Severe Storms And Flooding Associated With Tropical Depression Frances | Sep 8, 2004 |
| Severe Storms, Tornadoes,and Flooding | May 31, 1998 |
| Severe Storms And Flooding | Jan 19, 1996 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
621 since 1996: 496 flash floods and 125 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jun 28, 2025 | $2,000 |
| Flash Flood | Jun 28, 2025 | $5,000 |
| Flash Flood | Jun 27, 2025 | $5,000 |
| Flash Flood | Jun 27, 2025 | $20,000 |
| Flash Flood | Jun 26, 2025 | $10,000 |
| Flash Flood | Jun 26, 2025 | $50,000 |
| Flash Flood | May 21, 2025 | — |
| Flash Flood | Jun 17, 2025 | $5,000 |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Jun 28, 2025. A warm, moist airmass remained in place through the latter half of the month which allowed for daily shower and thunderstorm chances. Training storms was the primary factor to the resultant flash flooding as cells developed upshear of the initial updrafts in West Virginia, Ohio, and Pennsylvania. One of these storms did result in yet another round of flash flooding for portions of Wheeling WV.
Flash Flood · Jun 27, 2025. A warm, moist airmass remained in place through the latter half of the month which allowed for daily shower and thunderstorm chances. Training storms was the primary factor to the resultant flash flooding as cells developed upshear of the initial updrafts in West Virginia, Ohio, and Pennsylvania. One of these storms did result in yet another round of flash flooding for portions of Wheeling WV.
Flash Flood · Jun 26, 2025. A warm, moist airmass remained in place through the latter half of the month which allowed for daily shower and thunderstorm chances. Training storms was the primary factor to the resultant flash flooding as cells developed upshear of the initial updrafts in West Virginia, Ohio, and Pennsylvania. One of these storms did result in yet another round of flash flooding for portions of Wheeling WV.
Flash Flood · May 21, 2025. An occluding surface low slowly drifted across Ohio on May 21st. Bands of showers with embedded thunderstorms moved across southwest Pennsylvania. During the mid to late afternoon, one convective band, associated with ample 0-3km CAPE and surface vorticity, was able to generate four tornadoes across southwest PA. Three were relatively brief and weak, but one longer-track EF1 was noted in Washington County. Multip…
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Allegheny County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.