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Flood in Delaware County, Pennsylvania
258 floods and flash floods events in the NCEI Storm Events record, 1950 to 2026. Event types counted: Flood, Flash Flood, Coastal Flood, Lakeshore Flood.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. Storm records through 30 Jun 2026.
Delaware County, Pennsylvania, has 258 flood events in the NCEI record since 1950, with at least one in 30 different years.
August is the busiest month, with 56 of the recorded events. The last 20 years account for 196 events against 62 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 3.7% of the 7,057 flood events recorded in Pennsylvania; its 140.4 per 100 square miles compares with 15.8 statewide.
NCEI attributes 1 death in the county to floods and flash floods.
Compared with Pennsylvania
| Measure | Delaware County | Pennsylvania | US |
|---|---|---|---|
| Flood events since 1950 | 258 | 7,057 | 183,559 |
| Per 100 square miles | 140.4 | 15.8 | 5.2 |
| Per 10,000 residents | 4.5 | 5.4 | 5.5 |
| Deaths recorded | 1 | 110 | 2,961 |
| Busiest month | August | July | June |
By year
Seasonality
14Feb
4Mar
11Apr
16May
14Jun
27Jul
44Aug
56Sep
31Oct
17Nov
7Dec
17
Recorded events
The 183 events kept for this page are the 120 most recent plus the 80 with the most damage, deaths or injuries out of 258. Magnitude is hail size, tornado rating or wind speed as recorded.
| Date | Event type | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|
| 15 Jun 2026 | Flash Flood | — | $5K | — | — | — | County |
| 14 Jun 2026 | Flash Flood | — | $5K | — | — | — | County |
| 14 Jun 2026 | Flash Flood | — | $5K | — | — | — | County |
| 14 Jun 2026 | Flash Flood | — | $5K | — | — | — | County |
| 20 May 2026 | Flash Flood | — | — | — | — | — | County |
| 31 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | $25K | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | $5K | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | $5K | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | $20K | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | $5K | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 9 Jul 2025 | Flash Flood | — | $30K | — | — | — | County |
| 8 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 8 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 8 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 30 May 2025 | Flash Flood | — | — | — | — | — | County |
| 16 May 2025 | Flash Flood | — | $15K | — | — | — | County |
| 16 May 2025 | Flash Flood | — | $20K | — | — | — | County |
| 16 May 2025 | Flash Flood | — | $15K | — | — | — | County |
| 16 May 2025 | Flash Flood | — | $10K | — | — | — | County |
| 12 Apr 2024 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 4 Apr 2024 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 9 Mar 2024 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 13 Jan 2024 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 10 Jan 2024 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 28 Dec 2023 | Flood | — | — | — | — | — | County |
| 18 Dec 2023 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 18 Dec 2023 | Flood | — | $300K | — | — | — | County |
| 25 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 9 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 9 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 8 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 27 Jun 2023 | Flash Flood | — | — | — | — | — | County |
| 27 Jun 2023 | Flash Flood | — | — | — | — | — | County |
| 23 Jun 2023 | Flash Flood | — | — | — | — | — | County |
| 23 Dec 2022 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 9 Jun 2022 | Flash Flood | — | — | — | — | — | County |
| 29 Oct 2021 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 28 Oct 2021 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 23 Sep 2021 | Flash Flood | — | — | — | — | — | County |
| 1 Sep 2021 | Flash Flood | — | $15M | — | — | — | County |
| 1 Sep 2021 | Flash Flood | — | $15M | — | — | — | County |
| 28 Aug 2021 | Flash Flood | — | — | — | — | — | County |
| 19 Aug 2021 | Flash Flood | — | — | — | — | — | County |
| 12 Jul 2021 | Flash Flood | — | — | — | — | — | County |
| 14 Jun 2021 | Flash Flood | — | — | — | — | — | County |
| 8 Jun 2021 | Flash Flood | — | — | — | — | — | County |
| 12 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2020 | Flash Flood | — | — | — | — | — | County |
| 14 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 14 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2019 | Flash Flood | — | — | — | — | — | County |
| 31 Jul 2019 | Flash Flood | — | — | — | — | — | County |
| 11 Jul 2019 | Flash Flood | — | — | — | — | — | County |
| 11 Jul 2019 | Flash Flood | — | — | — | — | — | County |
| 4 Jul 2019 | Flash Flood | — | — | — | — | — | County |
| 20 Jun 2019 | Flash Flood | — | — | — | — | — | County |
| 20 Jun 2019 | Flash Flood | — | — | — | — | — | County |
| 20 Jun 2019 | Flash Flood | — | — | — | — | — | County |
| 13 Jun 2019 | Flash Flood | — | — | — | — | — | County |
| 26 Nov 2018 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 10 Sep 2018 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 31 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 13 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 13 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 13 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 13 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 13 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 11 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 3 Jul 2018 | Flash Flood | — | — | — | — | — | County |
| 1 May 2014 | Flood | — | $1.0M | — | — | — | County |
| 30 Apr 2014 | Flood | — | $1.0M | — | — | — | County |
| 2 Sep 2013 | Flash Flood | — | $250K | — | — | — | County |
| 28 Aug 2011 | Flood | — | $250K | — | — | — | County |
| 16 Apr 2011 | Coastal Flood | — | $50K | — | — | — | Forecast zone |
| 1 Oct 2010 | Flood | — | $5.0M | — | — | — | County |
| 2 Aug 2009 | Flash Flood | — | $500K | — | — | — | County |
| 28 Jun 2006 | Flood | — | $500K | — | — | — | County |
| 28 Jun 2006 | Flash Flood | — | — | — | — | — | County |
| 28 Jun 2006 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 26 Jun 2006 | Flood | — | — | — | — | — | County |
| 2 Jun 2006 | Flash Flood | — | — | — | — | — | County |
| 31 Jan 2006 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 4 Jan 2006 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 16 Dec 2005 | Flood | — | — | — | — | — | County |
| 8 Oct 2005 | Flash Flood | — | — | — | — | — | County |
| 8 Oct 2005 | Flood | — | — | — | — | — | Forecast zone |
| 2 Apr 2005 | Flood | — | — | — | — | — | Forecast zone |
| 28 Mar 2005 | Flood | — | — | — | — | — | Forecast zone |
| 14 Jan 2005 | Flood | — | — | — | — | — | Forecast zone |
| 28 Nov 2004 | Flood | — | — | — | — | — | Forecast zone |
| 28 Sep 2004 | Flash Flood | — | — | — | — | — | County |
| 18 Sep 2004 | Flash Flood | — | — | — | — | — | County |
| 18 Sep 2004 | Flood | — | — | — | — | — | Forecast zone |
| 1 Aug 2004 | Flash Flood | — | $10M | — | — | — | County |
| 27 Jul 2004 | Flash Flood | — | — | — | — | — | County |
| 12 Jul 2004 | Flash Flood | — | — | — | — | — | County |
| 6 Feb 2004 | Flood | — | — | — | — | — | Forecast zone |
| 11 Dec 2003 | Flood | — | — | — | — | — | Forecast zone |
| 27 Oct 2003 | Flood | — | — | — | — | — | Forecast zone |
| 23 Sep 2003 | Flood | — | — | — | — | — | Forecast zone |
| 15 Sep 2003 | Flash Flood | — | — | — | — | — | County |
| 10 Aug 2003 | Flash Flood | — | — | — | — | — | County |
| 20 Jun 2003 | Flood | — | — | — | — | — | Forecast zone |
| 20 Mar 2003 | Flood | — | — | — | — | — | Forecast zone |
| 22 Feb 2003 | Flood | — | — | — | — | — | Forecast zone |
| 22 Feb 2003 | Flash Flood | — | — | — | — | — | County |
| 17 Nov 2002 | Flash Flood | — | — | — | — | — | County |
| 16 Jun 2001 | Flash Flood | — | — | — | — | — | County |
| 17 Dec 2000 | Flash Flood | — | — | — | — | — | County |
| 27 Jul 2000 | Flash Flood | — | — | — | — | — | County |
| 21 Mar 2000 | Flash Flood | — | — | — | — | 3 | County |
| 16 Sep 1999 | Flash Flood | — | $15M | — | 1 | 14 | County |
| 16 Sep 1999 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 26 Aug 1999 | Flash Flood | — | — | — | — | — | County |
| 24 May 1999 | Flood | — | — | — | — | — | County |
| 21 Mar 1999 | Flash Flood | — | — | — | — | — | County |
| 3 Jan 1999 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 17 Aug 1998 | Flood | — | — | — | — | — | County |
| 12 May 1998 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 2 Apr 1998 | Flood | — | — | — | — | — | Forecast zone |
| 25 Jan 1997 | Flood | — | — | — | — | — | Forecast zone |
| 14 Dec 1996 | Flood | — | — | — | — | — | Forecast zone |
| 13 Dec 1996 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 6 Dec 1996 | Coastal Flood | — | — | — | — | — | Forecast zone |
| 2 Dec 1996 | Flash Flood | — | — | — | — | — | County |
| 19 Oct 1996 | Flood | — | — | — | — | — | Forecast zone |
| 19 Oct 1996 | Flash Flood | — | — | — | — | — | County |
| 13 Aug 1996 | Flash Flood | — | — | — | — | — | County |
| 16 Apr 1996 | Flash Flood | — | — | — | — | — | County |
| 27 Jan 1996 | Flood | — | — | — | — | — | Forecast zone |
| 19 Jan 1996 | Flood | — | $100K | — | — | — | Forecast zone |
| 19 Jan 1996 | Flash Flood | — | — | — | — | — | County |
Questions and answers
How many flood events has Delaware County had?
258 events in the NCEI Storm Events record between 1950 and 2026. Reporting of floods and flash floods became far more complete after 1996, so early decades undercount.
When was the last recorded flood event in Delaware County?
15 Jun 2026 (Flash Flood). Records reach NCEI about 120 days after the month ends.
What was the most damaging flood event recorded in Delaware County?
The flash flood of 1 Sep 2021, with property damage estimated by NCEI at $15M.
How does Delaware County compare with Pennsylvania for flood?
140.4 events per 100 square miles against 15.8 statewide; the county holds 258 of the state's 7,057 recorded events.
Provenance
NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026, public domain. County-recorded events plus zone-recorded events whose forecast zone is named for the county (marked "Forecast zone"). Population and area from the US Census Bureau (2021). Built 1 Oct 2026. See the methodology, the Flood hub and the county page.