Tornadoes · United States · New Jersey · 1997

F1 tornado, West Milford, New Jersey, September 11, 1997

This F1 tornado ran 0.3 miles across Passaic County on September 11, 1997, touching down at 3:10 PM EDT and reaching 50 yards wide. It killed nobody, and did $530,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mph

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

  2. F173 to 112 mphthis tornado

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

  3. F2113 to 157 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. F3158 to 206 mph

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

  5. F4207 to 260 mph

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

  6. F5261 to 318 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.

The record

Rating
F1
Date
September 11, 1997
Touchdown
3:10 PM EDT (19:10 UTC)
Path length
0.3 miles (0.5 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$530,000
County
Passaic County
Touchdown point
41.130, -74.380
Lift-off point
41.130, -74.380
Record number
495

What the Weather Service recorded

Lines of heavy showers and thunderstorms developed in a moist unstable airmass ahead of a slow moving cold front. As the lines moved slowly north, a thunderstorm produced a weak (F1) short-lived (about 30 seconds) tornado in West Milford township.The tornado formed in the Wonder Lake area just east of Germantown Road (off Route 23 North) and moved north. It was confirmed by National Weather Service Meteorologists.High winds downed about 150 trees, two of which fell through a house and the Wonder Lake Clubhouse. At least 4 trees fell on and damaged cars. High winds also downed numerous power lines.Heavy rain also caused flooding of streets and poor drainage areas. Here are selected rainfall amounts for Western Passaic County:Charlotteburg - 4.83 inchesGreenwood Lake - 4.34 inchesWest Milford - 4.18 inches.

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

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

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 forecast that day

The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 06:00 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 air that afternoon

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.

Brookhaven, NY (KOKX), 12:00Z

7.2 hours before the tornado, 131 km from the path. September 11, 1997.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 1997-09-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2 joules per kilogram, CIN -81, lifted condensation level 492 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Brookhaven, NY at 12:00Z on 1997-09-11The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 106 square meters per square second, 0 to 6 km bulk shear 37 knots.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
2 J/kg
Mixed-layer CIN
-81 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
492 m above ground
0-6 km bulk shear
37 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
106 m²/s²
0-3 km storm-relative helicity
201 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.5 K/km

Open this sounding in Storm Lab

Brookhaven, NY (KOKX), 00:00Z

4.8 hours after it, 131 km from the path. September 12, 1997.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 00:00Z on 1997-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1126 joules per kilogram, CIN -10, lifted condensation level 537 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Brookhaven, NY at 00:00Z on 1997-09-12The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 173 square meters per square second, 0 to 6 km bulk shear 34 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
1126 J/kg
Mixed-layer CIN
-10 J/kg
Surface CAPE
534 J/kg
Mixed-layer LCL
537 m above ground
0-6 km bulk shear
34 kt
0-1 km bulk shear
35 kt
0-1 km storm-relative helicity
173 m²/s²
0-3 km storm-relative helicity
142 m²/s²
Significant tornado parameter
0.8
Supercell composite
6.5
0-3 km lapse rate
5.9 K/km

Open this sounding in Storm Lab

The surface observations

Caldwell/Essex Co. (CDW), 29 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
17:45 UTC73.468170° 10 kt1015.2
18:45 UTC75.268130° 10 kt201014.2
19:45 UTC75.268150° 10 kt201014.6
20:45 UTC73.468140° 13 kt181014.2

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Brookhaven radar (KOKX), 131 km away, was scanning. The volume nearest the touchdown began at 19:08 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.

This ground now

The live radar over the trackEvery 1997 tornado in New JerseyEvery tornado in New Jersey since 1950Warnings in force in New Jersey nowThe forecast where you are

The other tornadoes of September 11, 1997

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 117:30 PM EDTF0Bucks, PA0.217$10,000

What this means

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.

Sources

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