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.
EF065 to 85 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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) | Expired | Product | Office |
|---|---|---|---|
| 09:00 UTC | 00:52 UTC | Flash Flood Watch | CTP |
| 15:37 UTC | 00:00 UTC | Tornado Watch | CTP |
| 19:10 UTC | 19:50 UTC | Tornado Warning | CTP |
| 21:10 UTC | 21:45 UTC | Severe Thunderstorm Warning | CTP |
| 21:35 UTC | 22:15 UTC | Severe Thunderstorm Warning | CTP |
| 21:38 UTC | 22:15 UTC | Severe Thunderstorm Warning | CTP |
| 22:13 UTC | 23:00 UTC | Severe Thunderstorm Warning | CTP |
| 22:37 UTC | 00:45 UTC | Flood Advisory | CTP |
| 22:47 UTC | 23:30 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 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.
- 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
Washington/Dulle, VA (KIAD), 00:00Z
4.7 hours after it, 114 km from the path. August 19, 2021.
- 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
The surface observations
Thomasville/York (THV), 16 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 17:20 UTC | 140° 10 kt | 1018.3 | ||||
| 17:25 UTC | 140° 11 kt | 1018.3 | ||||
| 17:30 UTC | 140° 8 kt | 1017.9 | -RA | |||
| 17:35 UTC | 130° 13 kt | 1017.9 | -RA | |||
| 17:40 UTC | 140° 13 kt | 1017.9 | -RA | |||
| 17:45 UTC | 140° 13 kt | 1017.9 | -RA | |||
| 17:50 UTC | 140° 11 kt | 1018.3 | -RA | |||
| 17:53 UTC | 78 | 74 | 140° 11 kt | 1017.9 | RA BR | |
| 17:55 UTC | 140° 9 kt | 1017.9 | RA BR | |||
| 18:00 UTC | 110° 7 kt | 1017.6 | -RA | |||
| 18:05 UTC | 130° 10 kt | 15 | 1017.6 | |||
| 18:10 UTC | 140° 11 kt | 1017.3 | ||||
| 18:15 UTC | 140° 9 kt | 1017.3 | ||||
| 18:20 UTC | 130° 11 kt | 1017.3 | ||||
| 18:25 UTC | 140° 11 kt | 1017.3 | ||||
| 18:30 UTC | 140° 13 kt | 1016.9 | ||||
| 18:35 UTC | 130° 13 kt | 18 | 1016.9 | |||
| 18:40 UTC | 140° 13 kt | 1016.9 | ||||
| 18:45 UTC | 140° 14 kt | 19 | 1016.9 | |||
| 18:50 UTC | 140° 11 kt | 1016.9 | ||||
| 18:53 UTC | 80 | 73 | 140° 9 kt | 19 | 1016.6 | -TSRA |
| 18:55 UTC | 130° 11 kt | 1016.6 | -RA | |||
| 19:00 UTC | 140° 15 kt | 1016.9 | RA | |||
| 19:01 UTC | 79 | 73 | 140° 14 kt | 20 | 1016.6 | TSRA |
| 19:05 UTC | 140° 13 kt | 1016.6 | +RA | |||
| 19:06 UTC | 78 | 73 | 150° 10 kt | 20 | 1016.6 | VCTS +RA |
| 19:10 UTC | 200° 7 kt | 1016.9 | -RA | |||
| 19:10 UTC | 78 | 73 | 200° 7 kt | 20 | 1016.9 | VCTS -RA |
| 19:12 UTC | 78 | 74 | 5 kt | 20 | 1016.9 | VCTS -RA BR |
| 19:15 UTC | 150° 7 kt | 1016.9 | -RA | |||
| 19:17 UTC | 78 | 74 | 130° 8 kt | 1016.6 | -TSRA | |
| 19:20 UTC | 13 kt | 1016.6 | ||||
| 19:25 UTC | 130° 14 kt | 1016.6 | ||||
| 19:30 UTC | 130° 13 kt | 18 | 1016.3 | |||
| 19:35 UTC | 140° 14 kt | 1016.3 | ||||
| 19:38 UTC | 82 | 76 | 150° 11 kt | 21 | 1016.3 | VCTS |
| 19:40 UTC | 160° 10 kt | 1016.3 | ||||
| 19:45 UTC | 150° 14 kt | 1016.3 | ||||
| 19:48 UTC | 82.4 | 75.2 | 150° 10 kt | 21 | 1016.3 | VCTS |
| 19:50 UTC | 150° 11 kt | 18 | 1016.3 | |||
| 19:53 UTC | 82 | 74 | 150° 9 kt | 21 | 1016.3 | VCTS |
| 19:55 UTC | 150° 11 kt | 1016.3 | ||||
| 20:00 UTC | 81 | 74 | 160° 8 kt | 16 | 1016.3 | -RA |
| 20:00 UTC | 160° 8 kt | 1016.3 | -RA | |||
| 20:05 UTC | 150° 10 kt | 1016.3 | -RA | |||
| 20:10 UTC | 150° 10 kt | 1015.9 | -RA | |||
| 20:15 UTC | 170° 5 kt | 1015.9 | -RA | |||
| 20:20 UTC | 170° 5 kt | 1015.9 | -RA | |||
| 20:25 UTC | 14 kt | 19 | 1015.9 | -RA | ||
| 20:30 UTC | 150° 16 kt | 21 | 1015.6 | |||
| 20:35 UTC | 150° 15 kt | 24 | 1015.6 | |||
| 20:40 UTC | 140° 11 kt | 1015.6 | -RA | |||
| 20:45 UTC | 150° 9 kt | 1015.6 | ||||
| 20:50 UTC | 160° 8 kt | 1015.6 | ||||
| 20:53 UTC | 83 | 75 | 160° 5 kt | 17 | 1015.6 | |
| 20:55 UTC | 160° 8 kt | 1015.6 | ||||
| 21:00 UTC | 150° 9 kt | 1015.6 | ||||
| 21:05 UTC | 170° 5 kt | 1015.6 | ||||
| 21:10 UTC | 170° 4 kt | 1015.6 | ||||
| 21:15 UTC | 150° 10 kt | 1015.2 |
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) | Report | Where | County | Remark |
|---|---|---|---|---|
| 17:10 UTC | TSTM WND DMG | 1 S Shermansdale | Perry, PA | TREES AND WIRES DOWN IN SHERMANS DALE. |
| 19:16 UTC | TORNADO | 2 Ene Heidlersburg | Adams, PA | NWS 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 UTC | TSTM WND DMG | 2 Ene New Oxford | Adams, PA | SEVERAL TREES DOWN NEAR THE INTERSECTION OF ROUTE 30 AND 94. |
| 19:39 UTC | TSTM WND DMG | 2 Wsw Siddonsburg | York, PA | TREES DOWN ON FILEYS ROAD. |
| 20:53 UTC | TSTM WND DMG | 2 Se Upper Strasburg | Franklin, PA | TREES DOWN ON WIRES. |
| 21:19 UTC | TSTM WND DMG | 2 Ene Waynesboro | Franklin, PA | TREES DOWN ON WIRES. |
| 21:35 UTC | TSTM WND DMG | 2 Wsw Pine Grove Furnac | Cumberland, PA | TREES DOWN ON WIRES. |
| 21:41 UTC | TSTM WND DMG | 1 Ene Duncannon | Perry, PA | TREES DOWN ON WIRES. |
| 21:43 UTC | TSTM WND DMG | 3 W Cashtown | Adams, PA | TREES DOWN ON WIRES. |
| 21:48 UTC | TSTM WND DMG | 1 Ne Halifax | Dauphin, PA | TREES DOWN ON WIRES. |
| 22:08 UTC | TSTM WND DMG | 1 Nne Mount Holly Sprin | Cumberland, PA | TREES DOWN ON WIRES. |
| 22:08 UTC | TSTM WND DMG | 3 Wsw Hogestown | Cumberland, PA | TREES 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.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| August 18 | 12:46 PM EDT | EF0 | Schuylkill, PA | 0.1 | 10 | $20,000 | ||
| August 18 | 4:35 PM EDT | EF0 | Snyder, PA | 0.5 | 15 | $4,000 | ||
| August 18 | 6:31 PM EDT | EF1 | Dauphin, PA | 5.5 | 150 | $20,000 | ||
| August 18 | 8:35 PM EDT | EF0 | York, PA | 0.7 | 125 | $20,000 | ||
| August 18 | 9:15 PM EDT | EF1 | Berks, PA | 1.1 | 125 | |||
| August 18 | 12:25 AM EDT | EF1 | Montgomery, PA | 8.8 | 140 |
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.