Tornadoes · United States · Pennsylvania · 1997
F0 tornado, Wharton, Pennsylvania, July 18, 1997
This F0 tornado ran 2.0 miles across Potter County on July 18, 1997, touching down at 3:35 PM EDT and reaching 100 yards wide. It killed nobody.
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.
F040 to 72 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- F0
- Date
- July 18, 1997
- Touchdown
- 3:35 PM EDT (19:35 UTC)
- Path length
- 2.0 miles (3.2 km)
- Path width
- 100 yards (91 m)
- Deaths
- 0
- Injuries
- 0
- County
- Potter County
- Touchdown point
- 41.530, -78.020
- Lift-off point
- 41.530, -78.020
- Record number
- 467
What the Weather Service recorded
41/30/25N, 77/57/53W to 41/28/55N, 77/55/55W. An F0 tornado touched down in the extreme southwest corner of Potter County southeast of Wharton shortly after 3:30 p.m. EDT. The storm moved southeast, damaging trees along a narrow 2-mile path between Montour and Trout Run Roads.
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.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 19:02 UTC | 20:00 UTC | Severe Thunderstorm Warning | CTP |
| 20:01 UTC | 21:20 UTC | Severe Thunderstorm Warning | CTP |
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 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.
Buffalo Intl Airport, NY (KBUF), 12:00Z
7.6 hours before the tornado, 165 km from the path. July 18, 1997.
- Mixed-layer CAPE
- 7 J/kg
- Mixed-layer CIN
- -94 J/kg
- Surface CAPE
- 654 J/kg
- Mixed-layer LCL
- 1353 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- -2 m²/s²
- 0-3 km storm-relative helicity
- 132 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
- 0-3 km lapse rate
- 5.7 K/km
Buffalo Intl Airport, NY (KBUF), 00:00Z
4.4 hours after it, 165 km from the path. July 19, 1997.
- Mixed-layer CAPE
- 380 J/kg
- Mixed-layer CIN
- -63 J/kg
- Surface CAPE
- 803 J/kg
- Mixed-layer LCL
- 1164 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- -23 m²/s²
- 0-3 km storm-relative helicity
- 45 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
- 0-3 km lapse rate
- 6.7 K/km
The radar
The State College radar (KCCX), 68 km away, was scanning. The volume nearest the touchdown began at 19:36 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 PennsylvaniaEvery tornado in Pennsylvania since 1950Warnings in force in Pennsylvania nowThe forecast where you are
The other tornadoes of July 18, 1997
9 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| July 18 | 4:02 AM CDT | F0 | Day, SD | 0.3 | 23 | |||
| July 18 | 2:47 PM CDT | F0 | Walworth, WI | 0.1 | 50 | |||
| July 18 | 3:30 PM CDT | F1 | DuPage, IL | 3.0 | 150 | |||
| July 18 | 4:35 PM EDT | F1 | Clinton, PA | 3.5 | 880 | |||
| July 18 | 4:45 PM EDT | F0 | Union, PA | 1.0 | 440 | |||
| July 18 | 3:50 PM CDT | F1 | Will, IL | 2.0 | 150 | 2 | ||
| July 18 | 5:15 PM EDT | F0 | Union, PA | 2.3 | 100 | |||
| July 18 | 5:17 PM EDT | F0 | Northumberland, PA | 2.3 | 100 | |||
| July 18 | 6:02 PM CDT | F0 | Baldwin, AL | 0.1 | 30 |
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.