Tornadoes · United States · Pennsylvania · 2005

F1 tornado, Hillsgrove, Pennsylvania, August 12, 2005

This F1 tornado ran 0.7 miles across Sullivan County on August 12, 2005, touching down at 4:22 PM EDT and reaching 30 yards wide. It killed nobody, and did $10,000 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
August 12, 2005
Touchdown
4:22 PM EDT (20:22 UTC)
Path length
0.7 miles (1.1 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
Property damage
$10,000
County
Sullivan County
Touchdown point
41.450, -76.720
Lift-off point
41.450, -76.720
Record number
325

What the Weather Service recorded

A tornado touched down during the afternoon of August 12th just north of the town of Hillsgrove in Sullivan County. A swath of tree damage about 1/2 to 3/4 miles long and about 30 yards wide ran along Mill Creek Road. It was estimated that the tornado was on the ground for 2 minutes. The tornado caused dozens of trees to be knocked down. In addition to the tornado, ambient winds with the thunderstorm produced downed trees throughout the general area of Hillsgrove. One of these trees fell on a vehicle causing major damage and others fell on structures causing minor to moderate roof damage. Winds were estimated at around 75 to 85 mph, making it an F1 on the Fujita Scale. There were no injuries or deaths.

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

The warnings

10 minutes of warning. NWS CTP issued a tornado warning for this county at 20:12 UTC, 10 minutes before the tornado touched down, in force until 21:15 UTC.

Issued (UTC)ExpiredProductOffice
19:57 UTC21:15 UTCSevere Thunderstorm WarningCTP
20:12 UTC21:15 UTCTornado 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. The outlook in force was issued at 20:09 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.

Phillips Aaf/Abe, MD (KAPG), 12:00Z

8.4 hours before the tornado, 226 km from the path. August 12, 2005.

Skew-T log-pSkew-T log-p diagram, Phillips Aaf/Abe, MD at 12:00Z on 2005-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 215 joules per kilogram, CIN -62, lifted condensation level 1361 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, Phillips Aaf/Abe, MD at 12:00Z on 2005-08-12The 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 61 square meters per square second, 0 to 6 km bulk shear 21 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
215 J/kg
Mixed-layer CIN
-62 J/kg
Surface CAPE
2690 J/kg
Mixed-layer LCL
1361 m above ground
0-6 km bulk shear
21 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
61 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

The radar

The Binghamton radar (KBGM), 103 km away, was scanning. The volume nearest the touchdown began at 20:21 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
19:55 UTCTSTM WND DMGUlsterBradford, PATREES DOWN THROUGHOUT THE NORTHEASTERN PART OF THE COUNTY.
20:20 UTCTSTM WND DMG9 N Muncy ValleySullivan, PAMULTIPLE TREES/WIRES DOWN
20:30 UTCHAIL 1ShunkSullivan, PA
21:10 UTCHAIL 0.25TowandaBradford, PAALSO TREES DOWN.
21:10 UTCHAIL 0.75TowandaBradford, PAALSO TREES DOWN.
21:10 UTCTORNADOTowandaBradford, PAPOSSIBLE TORNADO. NWS SURVEY TO BE CONDUCTED SATURDAY.
21:15 UTCTSTM WND DMGCentralColumbia, PATREES/WIRES/POLES DOWN
21:25 UTCTSTM WND DMGRed RockLuzerne, PATREES AND POWER LINES DOWN IN FAIRMOUNT AND ROSS TWPS.

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

This ground now

The live radar over the trackEvery 2005 tornado in PennsylvaniaEvery tornado in Pennsylvania since 1950Warnings in force in Pennsylvania nowThe forecast where you are

The other tornadoes of August 12, 2005

7 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 122:24 PM EDTF0Allegany, NY0.510$10,000
August 122:45 PM EDTF1Steuben, NY1.0200$50,000
August 125:10 PM EDTF0Bradford, PA1.0200$100,000
August 125:56 PM EDTF0Polk, FL0.540
August 124:40 PM MDTF2Campbell, WY1.5450213$5.0 million
August 127:05 PM MDTF0Converse, WY0.130
August 129:45 PM EDTF1Nassau, NY0.250$140,000

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.