Tornadoes · United States · Pennsylvania · 1981

F1 tornado, Beaver County, Pennsylvania, June 21, 1981

This F1 tornado ran 0.1 miles across Beaver County on June 21, 1981, touching down at 3:50 PM EDT and reaching 10 yards wide. It killed nobody, and did $5,000 to $50,000 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
June 21, 1981
Touchdown
3:50 PM EDT (19:50 UTC)
Path length
0.1 miles (0.2 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
Property damage
$5,000 to $50,000
County
Beaver County
Touchdown point
40.750, -80.170
Record number
480

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.

Pittsburgh, PA (KPIT), 12:00Z

7.8 hours before the tornado, 38 km from the path. June 21, 1981.

Skew-T log-pSkew-T log-p diagram, Pittsburgh, PA at 12:00Z on 1981-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 342 joules per kilogram, CIN -110, lifted condensation level 957 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, Pittsburgh, PA at 12:00Z on 1981-06-21The 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 205 square meters per square second, 0 to 6 km bulk shear 55 knots.1939587897Sfc1 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
342 J/kg
Mixed-layer CIN
-110 J/kg
Surface CAPE
206 J/kg
Mixed-layer LCL
957 m above ground
0-6 km bulk shear
55 kt
0-1 km bulk shear
24 kt
0-1 km storm-relative helicity
205 m²/s²
0-3 km storm-relative helicity
263 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.4
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

Pittsburgh, PA (KPIT), 00:00Z

4.2 hours after it, 38 km from the path. June 22, 1981.

Skew-T log-pSkew-T log-p diagram, Pittsburgh, PA at 00:00Z on 1981-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 123 joules per kilogram, CIN -27, lifted condensation level 699 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, Pittsburgh, PA at 00:00Z on 1981-06-22The 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 93 square meters per square second, 0 to 6 km bulk shear 35 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
123 J/kg
Mixed-layer CIN
-27 J/kg
Surface CAPE
157 J/kg
Mixed-layer LCL
699 m above ground
0-6 km bulk shear
35 kt
0-1 km bulk shear
20 kt
0-1 km storm-relative helicity
93 m²/s²
0-3 km storm-relative helicity
172 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3
0-3 km lapse rate
5.6 K/km

Open this sounding in Storm Lab

The surface observations

Pittsburgh International (PIT), 29 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
18:00 UTC7866270° 12 kt1011.9DZ
19:00 UTC7867190° 9 kt1011.5DZ
19:35 UTC260° 20 kt361011.5-SHRA DZ
20:00 UTC6965250° 16 kt1011.5-TSRA DZ
20:35 UTC260° 10 kt1010.8-SHRA DZ
21:00 UTC6865280° 10 kt1010.5-SHRA DZ

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

This ground now

The live radar over the trackEvery 1981 tornado in PennsylvaniaEvery tornado in Pennsylvania since 1950Warnings in force in Pennsylvania nowThe forecast where you are

The other tornadoes of June 21, 1981

36 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
June 212:10 AM CDTF2Warren, MO6.530016$50,000 to $500,000
June 214:00 AM CDTF0Riley, KS0.517
June 215:00 AM CDTF1Knox, NE0.540$50,000 to $500,000
June 2111:14 AM EDTF1Darke, OH2.3150$50,000 to $500,000
June 211:15 PM EDTF0Broward, FL0.120$5,000 to $50,000
June 211:30 PM EDTF1Union, OH1.91003$50,000 to $500,000
June 212:15 PM EDTF0Knox, OH2.0150$500 to $5,000
June 213:21 PM EDTF0Columbiana, OH1.0100$500 to $5,000
June 214:30 PM EDTF1Allegheny, PA0.110$5,000 to $50,000
June 213:45 PM CDTF0Brown, SD0.110
June 214:00 PM CDTF0Norman, MN1.020$500 to $5,000
June 215:10 PM EDTF1Orange, FL0.530$50,000 to $500,000
June 215:20 PM EDTF0Lawrence, OH1.0100$5,000 to $50,000
June 215:30 PM EDTF1Luzerne, PA3.317$5,000 to $50,000
June 214:30 PM CDTF1Lac qui Parle, MN2.050$5,000 to $50,000
June 214:38 PM CDTF2Yellow Medicine, MN54.3200$50,000 to $500,000
June 216:00 PM EDTF0Orange, FL0.120$500 to $5,000
June 216:00 PM EDTF0Orange, FL0.120$50 to $500
June 216:15 PM EDTF1Burlington, NJ0.110$50,000 to $500,000
June 216:30 PM EDTF2Marion, WV1.010$50,000 to $500,000
June 215:47 PM CDTF0Redwood, MN2.033
June 216:28 PM CDTF0Brown, MN12.050
June 216:45 PM CDTF1Watonwan, MN15.650$5,000 to $50,000
June 217:45 PM EDTF1Van Wert, OH2.7150$50,000 to $500,000
June 216:58 PM CDTF0Jackson, MO1.050
June 217:14 PM CDTF0Jackson, MO1.050
June 217:14 PM CDTF0Cass, MO1.050
June 217:38 PM CDTF0Jackson, MO0.350$50 to $500
June 218:14 PM CDTF1Hancock, IL0.110$500,000 to $5 million
June 218:47 PM CDTF1Hancock, IL0.110$500 to $5,000
June 218:56 PM CDTF3Schuyler, IL8.8880112$500,000 to $5 million
June 219:05 PM CDTF0Cass, MO1.050
June 219:10 PM CDTF0Osage, MO1.050$50 to $500
June 219:33 PM CDTF0McLean, IL0.110
June 2110:00 PM CDTF0Adams, IL0.110
June 2110:16 PM CDTF0McLean, IL0.350

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.