EF0 tornado, Clarksville to Penns Neck, New Jersey, September 1, 2021

1. EF065 to 85 mphthis tornado

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF0

Date

September 1, 2021

Touchdown

7:32 PM EDT (23:32 UTC)

Lifted

7:35 PM EDT (23:35 UTC)

On the ground

3 minutes

Path length

2.6 miles (4.2 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

County

Mercer County

Touchdown point

40.310, -74.670

Lift-off point

40.340, -74.640

Record number

2109011732-01

26 damage points were recorded along this path by NWS PHI, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 104 mph.

• Flooding may have helped trees uproot.
• Trees uprooted and brought down power lines and poles.
• Decent size limbs with at least one small uproot
• May be a mix of flooding damage and wind damage in this area.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

The remnants of Hurricane Ida impacted the mid-Atlantic on September 1, 2021. As it moved northward, Ida began transitioning to a strong mid-latitude cyclone with pronounced frontal features, but with continued tropical moisture. On a regional level, the remnants of Ida became one of the most severe natural disasters in US history, due to a combination of several tornadoes, some of them strong, as well as catastrophic flooding over a large and densely populated area. The severe weather threat unfolded as the system's developing warm front lifted northward from the Delmarva region into Pennsylvania and New Jersey. South of the warm front, partial clearing and moderate to strong instability developed. Meanwhile, very strong shear and forcing, along with tropical moisture, were present within the warm sector. The result was widespread convection in the form of both supercell and quasi-linear thunderstorms. A number of storms became severe across the region, producing several tornadoes and other instances of wind damage. This continued an exceptionally active stretch of high end severe weather in the region, coming barely a month after the tornado outbreak of July 29.

A tornado touched down along Emmons Drive along Route 1 in |Princeton, NJ as a remnant supercell moved northward after |producing the Mullica Hill and Burlington, NJ tornadoes earlier |Wednesday afternoon as Ida's remnants moved through the region. |Damage first occurred as several small branches were brought down |along the Whole Foods and Wendy's parking lots along Route 1 in |far eastern Princeton Township, with a continued path of minor |branch damage extending northward along Farber Road, Meadow Drive,|and Canal Pointe Boulevard adjacent to Route 1. Several medium-|size trees were also uprooted with numerous small branches having |been brought down along the western periphery of the Marketfair |shopping parking lot. ||From there, the tornado continued northward with minor tree |damage having occurred along Carnegie Center Boulevard as the |tornado moved northward. Several small branches were also brought |down in a residential area along Heritage Boulevard with one pine |tree even having been snapped. An additional pine tree was also |uprooted along Alexander Road near Glenview. The tornado then |snapped several small hardwood trees, knocking down several |utility poles and power lines along Washington Road. A tree was |also uprooted along Lower Harrison Street along Carnegie Lake |before the tornado lifted somewhere over the lake.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

10 minutes of warning. NWS PHI issued a tornado warning for this county at 23:22 UTC, 10 minutes before the tornado touched down, in force until 23:33 UTC.

The county was under a tornado watch, issued at 16:41 UTC and running to 01:54 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Enhanced Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:46 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

The Philadelphia radar (KDIX), 47 km away, was scanning. The volume nearest the touchdown began at 23:29 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2021 tornado in New JerseyEvery tornado in New Jersey since 1950Warnings in force in New Jersey nowThe forecast where you are

10 more were confirmed in the United States that day.

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.