EF0 tornado, Turpin, Oklahoma, August 7, 2013

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.

Rating

EF0

Date

August 7, 2013

Touchdown

7:36 PM CDT (00:36 UTC)

Lifted

7:42 PM CDT (00:42 UTC)

On the ground

6 minutes

Path length

0.1 miles (0.2 km)

Path width

25 yards (23 m)

Deaths

0

Injuries

0

County

Beaver County

Touchdown point

36.851, -100.939

Lift-off point

36.851, -100.939

Record number

1308071836-01

1 damage points were recorded along this path by NWS AMA, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 65 mph.

• Brief EF0 tornado confirmed by photo evidence from Sheriff's office. Width: 25 yards Length: 200 yards

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

The combination of a moderately unstable atmosphere, decent deep layer shear, and the presence of a stalled frontal boundary led to a severe weather outbreak during the evening and overnight hours of the 7th. The 6 PM CST upper air soundings out of Amarillo, Texas and Dodge City, Kansas showed surface based instability between 1700 and 2500 J/kg with deep layer shear around 32 kt across the Oklahoma Panhandle. As daytime heating maximized during the early afternoon discrete thunderstorms began developing across the western Texas and Oklahoma Panhandle. After briefly moving to the north these discrete thunderstorms turn to the right and began moving to the east across the panhandle. These discrete thunderstorms would produce hail across the Oklahoma Panhandle up to the size of baseballs. One discrete thunderstorm over eastern Texas County and western Beaver County developed near enough to the stationary boundary for the additional low level wind shear to help develop a brief tornado. The tornado lasted less than ten minutes and the parent thunderstorms quickly diminished as it moved eastward into Beaver County. By 7 PM CST, discrete thunderstorms over the western Oklahoma Panhandle began forming into a squall line. This line would go on to traverse the Oklahoma Panhandle producing 60 to 70 mph gusts and ping pong ball size hail before entering western Oklahoma by midnight of the 8th.

A weak EF0 tornado touched down 3.5 miles west-southwest of Turpin, Oklahoma during the evening hours of the 7th. A supercell thunderstorm spawned the tornado, which lasted for 6 minutes but produced no damage. The maximum wind speed was estimated to be 65 mph.

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. One was issued for the county at another hour that day.

The county was under a severe thunderstorm watch, issued at 22:33 UTC and running to 06:00 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 0.02 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.

Liberal_muni (LBL), 22 km from the path, in the two hours either side.

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

The Dodge City radar (KDDC), 133 km away, was scanning. The volume nearest the touchdown began at 00:33 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 2013 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

3 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.