63
Recorded events
0
Direct deaths
6
Direct injuries
$53.2M
Property damage
Flash Flood in Morris County, New Jersey: 63 recorded events between 1996 and 2025. The strongest on record measured 0. That places the county #413 nationally and #15 statewide for this hazard.
Decade by decade
Flash Flood in Morris County, New Jersey: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flash flood in Morris County is the 2010s, when 21 of the county's 63 recorded events were logged. Comparing decades is useful for spotting active periods, but the earliest years are thin because systematic reporting for this hazard began later.
Within the Morris County archive, flash flood makes up 9.7% of all recorded severe weather across 10 hazard types. Nationally the county sits at #413 for this hazard and #15 within New Jersey, putting it in the 86.5 percentile of all U.S. counties.
Seasonality
Events by month
Aug is the peak month for flash flood in Morris County with 18 recorded events, while Feb is the quietest. Seasonality here is a property of the archive as much as the climate: reports cluster where population and spotter networks are densest.
Significant events
Deadliest on record
| Date | Location | Scale | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Sep 16, 1999 | COUNTYWIDE | 0 | 0 | 6 | $30.0M |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Jul 31, 2025 | MT HOPE | 0 | $0 |
| Jul 14, 2025 | FLORHAM PARK | 0 | $0 |
| Jul 14, 2025 | CHATHAM | 0 | $0 |
| May 14, 2025 | CHATHAM | 0 | $0 |
| Aug 18, 2024 | DOVER | 0 | $0 |
| Aug 18, 2024 | BUTLER | 0 | $0 |
| Aug 18, 2024 | MT TABOR | 0 | $0 |
| Aug 18, 2024 | CONVENT STATION | 0 | $0 |
| Jul 14, 2023 | ROCKAWAY | 0 | $0 |
| Jun 26, 2023 | CEDAR KNOLLS | 0 | $0 |
Other hazards here
More from Morris County
- Thunderstorm Wind 349
- Hail 72
- Flood 59
- Lightning 49
- Heavy Rain 44
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Widespread flash flooding occurred in Morris County with numerous road closures. Many waterways in the county overflowed their banks, including the Passaic River, the Whippany River, the Pompton River and the Pequannock River.
The heavy rain caused flash flooding of smaller streams as well as poor drainage flooding in Morris County. The runoff also caused flooding along some of the larger rivers in the county including the Rockaway and Passaic which lasted for days. In Jefferson Township, flooding was reported along New Jersey State Route 15. An overflowing retention basin flooded a house in the township. In Mount Olive Township, three roads were closed including River Road. In Chester, Tanner Brook Road was closed. Four roads were closed in Lincoln Park and two roads were closed in Mendham Township. Basements were flooded in Morristown. Please refer to the separate storm data entry as flooding for specifics about flooded streams and rivers within the county. Event precipitation totals included 3.91 inches in Morris Township, 3.19 inches in Ironia, 2.64 inches in West Wharton and 2.30 inches in Boonton.
Thunderstorms which also produced torrential downpours caused flash flooding in Morristown in and near the Whippany Creek. Seven vehicles (two completely submerged) and basements sustained flood damage. Basements on Cobb Place were flooded. Three roadways within the town were closed. The heavy rain also helped a tree on Olyphant Drive topple onto two vehicles.||The Whippany Creek at Moorestown was above its 6 foot flood stage from 513 a.m. EDT through 603 a.m. EDT on the 8th. It crested at 6.35 feet at 530 a.m. EDT.
Quick answers
Frequently asked
How many flash flood events are on record in Morris County, New Jersey?
63 flash flood events are recorded in Morris County between 1996 and 2025, causing 0 direct deaths.
What is the strongest flash flood recorded in Morris County?
The strongest flash flood on record in Morris County measured 0.
Where does the flash flood data for Morris County come from?
All events come from the NOAA/NCEI Storm Events Database, the federal public-domain archive of severe weather reports. Dates are UTC, damage is as reported and not inflation-adjusted, and the most recent entries may still be revised.
Cite this page
“Flash Flood in Morris County, New Jersey.” Severe Weather History. severeweatherhistory.com/county/new-jersey/morris-county/flash-flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.