Tornadoes · United States · Pennsylvania · 2021

EF0 tornado, Hampton, Pennsylvania, August 18, 2021

This EF0 tornado ran 0.6 miles across Adams County on August 18, 2021, touching down at 3:16 PM EDT and reaching 75 yards wide. It killed nobody, and did $6,000 of property damage.

The rating scale

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

  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.

The record

Rating
EF0
Date
August 18, 2021
Touchdown
3:16 PM EDT (19:16 UTC)
Lifted
3:18 PM EDT (19:18 UTC)
On the ground
2 minutes
Path length
0.6 miles (1.0 km)
Path width
75 yards (69 m)
Deaths
0
Injuries
0
Property damage
$6,000
County
Adams County
Touchdown point
39.939, -77.062
Lift-off point
39.948, -77.058
Record number
2108181316-01

The damage survey

5 damage points were recorded along this path by NWS CTP, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 75 mph.

  • One dead tree was surveyed laying toward the NNE. NWS interviewed someone nearby who reported the tree fell on Wed afternoon. A spotter reported that additional trees had fallen in the wooded area across from Reading Twp Municipal Building.
  • Some corn crop was downed, pointing NW toward the tornado track.
  • Large branches were ripped off healthy maple trees and carried about 10-20 feet. They landed in a convergent pattern toward the ENE and NE.
  • A patch of corn crop was downed by the tornado. The downed corn points NW.

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

What the Weather Service recorded

An EF-0 tornado touched down west of East Berlin during the afternoon of August 18, 2021. The tornado had estimated peak winds near 65 mph, a path length of around 0.6 miles, and a maximum path width of 75 yards.

An EF-0 tornado touched down west of East Berlin during the afternoon of August 18, 2021. The tornado had estimated peak winds near 65 mph, a path length of around 0.6 miles, and a maximum path width of 75 yards. The tornado began near the Reading Township Municipal Building on Church Street, where a few trees were downed and several large branches were snapped. Debris was lying in a convergent pattern along the northeastward track. The tornado continued northeastward along or just west of Church Road. Some corn crop along Church Road was damaged, lying northwestward toward the tornado track.

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

The warnings

6 minutes of warning. NWS CTP issued a tornado warning for this county at 19:10 UTC, 6 minutes before the tornado touched down, in force until 19:50 UTC.

The county was under a tornado watch, issued at 15:37 UTC and running to 00:00 UTC.

Issued (UTC)ExpiredProductOffice
09:00 UTC00:52 UTCFlash Flood WatchCTP
15:37 UTC00:00 UTCTornado WatchCTP
19:10 UTC19:50 UTCTornado WarningCTP
21:10 UTC21:45 UTCSevere Thunderstorm WarningCTP
21:35 UTC22:15 UTCSevere Thunderstorm WarningCTP
21:38 UTC22:15 UTCSevere Thunderstorm WarningCTP
22:13 UTC23:00 UTCSevere Thunderstorm WarningCTP
22:37 UTC00:45 UTCFlood AdvisoryCTP
22:47 UTC23:30 UTCSevere Thunderstorm WarningCTP

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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 17:08 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.

Washington/Dulle, VA (KIAD), 12:00Z

7.3 hours before the tornado, 114 km from the path. August 18, 2021.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2021-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1011 joules per kilogram, CIN -1, lifted condensation level 592 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Washington/Dulle, VA at 12:00Z on 2021-08-18The 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 151 square meters per square second, 0 to 6 km bulk shear 30 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
1011 J/kg
Mixed-layer CIN
-1 J/kg
Surface CAPE
1825 J/kg
Mixed-layer LCL
592 m above ground
0-6 km bulk shear
30 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
175 m²/s²
Significant tornado parameter
0.6
Supercell composite
4.6
0-3 km lapse rate
5.3 K/km

Open this sounding in Storm Lab

Washington/Dulle, VA (KIAD), 00:00Z

4.7 hours after it, 114 km from the path. August 19, 2021.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 00:00Z on 2021-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1288 joules per kilogram, CIN -8, lifted condensation level 1100 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Washington/Dulle, VA at 00:00Z on 2021-08-19The 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 126 square meters per square second, 0 to 6 km bulk shear 30 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
1288 J/kg
Mixed-layer CIN
-8 J/kg
Surface CAPE
2372 J/kg
Mixed-layer LCL
1100 m above ground
0-6 km bulk shear
30 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
126 m²/s²
0-3 km storm-relative helicity
171 m²/s²
Significant tornado parameter
0.6
Supercell composite
5.9
0-3 km lapse rate
6.8 K/km

Open this sounding in Storm Lab

The surface observations

Thomasville/York (THV), 16 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
17:20 UTC140° 10 kt1018.3
17:25 UTC140° 11 kt1018.3
17:30 UTC140° 8 kt1017.9-RA
17:35 UTC130° 13 kt1017.9-RA
17:40 UTC140° 13 kt1017.9-RA
17:45 UTC140° 13 kt1017.9-RA
17:50 UTC140° 11 kt1018.3-RA
17:53 UTC7874140° 11 kt1017.9RA BR
17:55 UTC140° 9 kt1017.9RA BR
18:00 UTC110° 7 kt1017.6-RA
18:05 UTC130° 10 kt151017.6
18:10 UTC140° 11 kt1017.3
18:15 UTC140° 9 kt1017.3
18:20 UTC130° 11 kt1017.3
18:25 UTC140° 11 kt1017.3
18:30 UTC140° 13 kt1016.9
18:35 UTC130° 13 kt181016.9
18:40 UTC140° 13 kt1016.9
18:45 UTC140° 14 kt191016.9
18:50 UTC140° 11 kt1016.9
18:53 UTC8073140° 9 kt191016.6-TSRA
18:55 UTC130° 11 kt1016.6-RA
19:00 UTC140° 15 kt1016.9RA
19:01 UTC7973140° 14 kt201016.6TSRA
19:05 UTC140° 13 kt1016.6+RA
19:06 UTC7873150° 10 kt201016.6VCTS +RA
19:10 UTC200° 7 kt1016.9-RA
19:10 UTC7873200° 7 kt201016.9VCTS -RA
19:12 UTC7874 5 kt201016.9VCTS -RA BR
19:15 UTC150° 7 kt1016.9-RA
19:17 UTC7874130° 8 kt1016.6-TSRA
19:20 UTC 13 kt1016.6
19:25 UTC130° 14 kt1016.6
19:30 UTC130° 13 kt181016.3
19:35 UTC140° 14 kt1016.3
19:38 UTC8276150° 11 kt211016.3VCTS
19:40 UTC160° 10 kt1016.3
19:45 UTC150° 14 kt1016.3
19:48 UTC82.475.2150° 10 kt211016.3VCTS
19:50 UTC150° 11 kt181016.3
19:53 UTC8274150° 9 kt211016.3VCTS
19:55 UTC150° 11 kt1016.3
20:00 UTC8174160° 8 kt161016.3-RA
20:00 UTC160° 8 kt1016.3-RA
20:05 UTC150° 10 kt1016.3-RA
20:10 UTC150° 10 kt1015.9-RA
20:15 UTC170° 5 kt1015.9-RA
20:20 UTC170° 5 kt1015.9-RA
20:25 UTC 14 kt191015.9-RA
20:30 UTC150° 16 kt211015.6
20:35 UTC150° 15 kt241015.6
20:40 UTC140° 11 kt1015.6-RA
20:45 UTC150° 9 kt1015.6
20:50 UTC160° 8 kt1015.6
20:53 UTC8375160° 5 kt171015.6
20:55 UTC160° 8 kt1015.6
21:00 UTC150° 9 kt1015.6
21:05 UTC170° 5 kt1015.6
21:10 UTC170° 4 kt1015.6
21:15 UTC150° 10 kt1015.2

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

The radar

The Sterling radar (KLWX), 114 km away, was scanning. The volume nearest the touchdown began at 19:13 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.

What was reported nearby

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

Time (UTC)ReportWhereCountyRemark
17:10 UTCTSTM WND DMG1 S ShermansdalePerry, PATREES AND WIRES DOWN IN SHERMANS DALE.
19:16 UTCTORNADO2 Ene HeidlersburgAdams, PANWS CONFIRMS AN EF-0 TORNADO WITH EST MAX WIND 65 MPH. SEVERAL LARGE BRANCHES WERE SNAPPED AND A FEW TREES AND LARGE LIMBS WERE SNAPPED AND DOWNED IN THE AREA. EST PATH LENGTH 0.7 MILE., WIDTH 75 YDS.
19:24 UTCTSTM WND DMG2 Ene New OxfordAdams, PASEVERAL TREES DOWN NEAR THE INTERSECTION OF ROUTE 30 AND 94.
19:39 UTCTSTM WND DMG2 Wsw SiddonsburgYork, PATREES DOWN ON FILEYS ROAD.
20:53 UTCTSTM WND DMG2 Se Upper StrasburgFranklin, PATREES DOWN ON WIRES.
21:19 UTCTSTM WND DMG2 Ene WaynesboroFranklin, PATREES DOWN ON WIRES.
21:35 UTCTSTM WND DMG2 Wsw Pine Grove FurnacCumberland, PATREES DOWN ON WIRES.
21:41 UTCTSTM WND DMG1 Ene DuncannonPerry, PATREES DOWN ON WIRES.
21:43 UTCTSTM WND DMG3 W CashtownAdams, PATREES DOWN ON WIRES.
21:48 UTCTSTM WND DMG1 Ne HalifaxDauphin, PATREES DOWN ON WIRES.
22:08 UTCTSTM WND DMG1 Nne Mount Holly SprinCumberland, PATREES DOWN ON WIRES.
22:08 UTCTSTM WND DMG3 Wsw HogestownCumberland, PATREES DOWN ON WIRES.

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

This ground now

The live radar over the trackEvery 2021 tornado in PennsylvaniaEvery tornado in Pennsylvania since 1950Warnings in force in Pennsylvania nowThe forecast where you are

The other tornadoes of August 18, 2021

6 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 1812:46 PM EDTEF0Schuylkill, PA0.110$20,000
August 184:35 PM EDTEF0Snyder, PA0.515$4,000
August 186:31 PM EDTEF1Dauphin, PA5.5150$20,000
August 188:35 PM EDTEF0York, PA0.7125$20,000
August 189:15 PM EDTEF1Berks, PA1.1125
August 1812:25 AM EDTEF1Montgomery, PA8.8140

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.