EF1 tornado, Perdix to Dauphin, Pennsylvania, May 26, 2011

1. EF065 to 85 mph

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mphthis tornado

   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.

Rating

EF1

Date

May 26, 2011

Touchdown

7:20 PM EDT (23:20 UTC)

Lifted

7:24 PM EDT (23:24 UTC)

On the ground

4 minutes

Path length

2.6 miles (4.2 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

Property damage

$150,000

Counties

Dauphin and Perry counties

Touchdown point

40.343, -76.952

Lift-off point

40.370, -76.918

Record number

1105261720-01

A significant severe weather outbreak occurred across central Pennsylvania during the afternoon and evening hours on 26 May 2011. A total of 6 tornadoes were confirmed ranging from EF0-EF2 in magnitude with multiple reports of large hail and damaging thunderstorm winds. Flash flooding was also reported with Franklin County with these storms.

A NWS survey team confirmed a tornado which began in eastern Perry County, and crossed the Susquehanna River into western Dauphin County. The tornado touched down north of Route 850 in Perry County, between VFW Drive and Mountaindale Drive. The tornado tracked to the northeast, lifting occasionally as it moved across eastern Perry County and eventually to the Susquehanna River. The path indicated the tornado lifted and touched down several times. Damage was limited mainly to over 100 trees, which were snapped and uprooted. Photographic evidence helped in making the tornado declaration. ||After crossing the Susquehanna River, the tornado touched down again in Dauphin Borough. Examination of the damage here indicated the tornado touched down again about one quarter mile east of Dauphin Borough on River Road. The tornado continued east about 1.5 miles...generally following Hillside Road...and dissipating as it began to climb Second Mountain. Six homes suffered moderate to major damage, and 150 trees were downed. Storm damage was consistent with maximum winds of around 90 mph. There were no injuries or fatalities.||In addition to the tornadic damage, downburst/straight line wind damage was noted at least 1.5 miles to the west of Dauphin Borough along the river, and in eastern Perry County, also near the Susquehanna River.

A NWS survey team confirmed a tornado which began in eastern Perry County, and crossed the Susquehanna River into western Dauphin County. The tornado touched down north of Route 850 in Perry County, between VFW Drive and Mountaindale Drive. The tornado tracked to the northeast, lifting occasionally as it moved across eastern Perry County and eventually to the Susquehanna River. The path indicated the tornado lifted and touched down several times. Damage was limited mainly to over 100 trees, which were snapped and uprooted. Photographic evidence helped in making the tornado declaration. ||After crossing the Susquehanna River, the tornado touched down again in Dauphin Borough. Examination of the damage here indicated the tornado touched down again about one quarter mile east of Dauphin Borough on River Road. The tornado continued east about 1.5 miles...generally following Hillside Road...and dissipating as it began to climb Second Mountain. Six homes suffered moderate to major damage, and 150 trees were downed. Storm damage was consistent with maximum winds of around 90 mph. There were no injuries or fatalities.||In addition to the tornadic damage, downburst/straight line wind damage was noted at least 1.5 miles to the west of Dauphin Borough along the river, and in eastern Perry County, also near the Susquehanna River.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

The county was under a tornado watch, issued at 18:53 UTC and running to 02:00 UTC.

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 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 19:57 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 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.

The State College radar (KCCX), 110 km away, was scanning. The volume nearest the touchdown began at 23:20 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.

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

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

The live radar over the trackEvery 2011 tornado in PennsylvaniaEvery tornado in Pennsylvania since 1950Warnings in force in Pennsylvania nowThe forecast where you are

14 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.