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Flood in Ozaukee County, Wisconsin
45 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.
Ozaukee County, Wisconsin, has 45 flood events in the NCEI record since 1950, with at least one in 19 different years.
August is the busiest month, with 12 of the recorded events. The last 20 years account for 30 events against 15 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 1.7% of the 2,580 flood events recorded in Wisconsin; its 19.3 per 100 square miles compares with 4.8 statewide.
NCEI attributes 1 death in the county to floods and flash floods.
Compared with Wisconsin
| Measure | Ozaukee County | Wisconsin | US |
|---|---|---|---|
| Flood events since 1950 | 45 | 2,580 | 183,559 |
| Per 100 square miles | 19.3 | 4.8 | 5.2 |
| Per 10,000 residents | 4.9 | 4.4 | 5.5 |
| Deaths recorded | 1 | 30 | 2,961 |
| Busiest month | August | June | June |
By year
Seasonality
1Feb
2Mar
3Apr
5May
6Jun
9Jul
2Aug
12Sep
1Oct
4Nov
0Dec
0
Recorded events
All 45 events, most recent first. Magnitude is hail size, tornado rating or wind speed as recorded.
| Date | Event type | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|
| 14 Apr 2026 | Flash Flood | — | $5K | — | — | — | County |
| 11 Aug 2025 | Flood | — | $4K | $1K | — | — | County |
| 10 Aug 2025 | Flood | — | $1K | $1K | — | — | County |
| 10 Aug 2025 | Flash Flood | — | $450K | $1K | — | — | County |
| 10 Aug 2025 | Flash Flood | — | $50K | $1K | — | — | County |
| 10 Aug 2025 | Flood | — | $1K | $1K | — | — | County |
| 19 Apr 2023 | Flood | — | $2K | — | — | — | County |
| 7 Aug 2021 | Flash Flood | — | $1K | — | — | — | County |
| 18 May 2020 | Flood | — | $2K | — | — | — | County |
| 17 May 2020 | Lakeshore Flood | — | — | — | — | 2 | Forecast zone |
| 17 May 2020 | Flood | — | $30K | — | 1 | — | County |
| 11 Jan 2020 | Lakeshore Flood | — | $65K | — | — | — | Forecast zone |
| 2 Oct 2019 | Flood | — | $2K | — | — | — | County |
| 2 Oct 2019 | Flood | — | $5K | — | — | — | County |
| 2 Oct 2019 | Flood | — | $2K | — | — | — | County |
| 1 Oct 2019 | Flash Flood | — | $10K | — | — | — | County |
| 15 Mar 2019 | Flood | — | $10K | — | — | — | County |
| 14 Mar 2019 | Flood | — | $1K | — | — | — | County |
| 14 Mar 2019 | Flood | — | $1K | — | — | — | County |
| 1 Sep 2018 | Flood | — | $1K | — | — | — | County |
| 27 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 27 Aug 2018 | Flood | — | $854K | $5K | — | — | County |
| 27 Aug 2018 | Flood | — | $1K | — | — | — | County |
| 26 Aug 2018 | Flash Flood | — | — | — | — | — | County |
| 14 Apr 2018 | Lakeshore Flood | — | — | — | — | — | Forecast zone |
| 14 Apr 2014 | Flood | — | — | — | — | — | County |
| 10 Apr 2013 | Flood | — | $5K | $1K | — | — | County |
| 22 Jul 2010 | Flash Flood | — | $20K | $1K | — | — | County |
| 12 Jun 2008 | Flash Flood | — | $462K | $300K | — | — | County |
| 26 Jul 2007 | Flash Flood | — | $100K | — | — | — | County |
| 1 Jun 2004 | Flood | — | $2.6M | $5.0M | — | — | Forecast zone |
| 23 May 2004 | Flood | — | $135K | — | — | — | Forecast zone |
| 21 Aug 2002 | Flood | — | — | — | — | — | County |
| 13 Aug 2002 | Flood | — | — | — | — | 1 | County |
| 9 Feb 2001 | Flood | — | $20K | — | — | — | Forecast zone |
| 17 May 2000 | Flash Flood | — | $75K | — | — | — | County |
| 16 May 1999 | Flood | — | — | — | — | — | County |
| 21 Jun 1997 | Flash Flood | — | $3.6M | — | — | — | County |
| 18 Jun 1996 | Flash Flood | — | $200K | — | — | — | County |
| 18 Jun 1996 | Flood | — | — | — | — | — | County |
| 18 Jun 1996 | Flash Flood | — | $5.3M | — | — | — | County |
| 18 Jun 1996 | Flash Flood | — | $1.0M | — | — | — | County |
| 18 Jun 1996 | Flood | — | $3.9M | $3.0M | — | — | Forecast zone |
| 17 Jun 1996 | Flash Flood | — | $200K | — | — | — | County |
| 27 Feb 1996 | Flood | — | — | — | — | — | Forecast zone |
Questions and answers
How many flood events has Ozaukee County had?
45 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 Ozaukee County?
14 Apr 2026 (Flash Flood). Records reach NCEI about 120 days after the month ends.
What was the most damaging flood event recorded in Ozaukee County?
The flood of 1 Jun 2004, with property damage estimated by NCEI at $2.6M and crop damage at $5.0M.
How does Ozaukee County compare with Wisconsin for flood?
19.3 events per 100 square miles against 4.8 statewide; the county holds 45 of the state's 2,580 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.