Tornadoes · United States · Oklahoma · 2021

Unrated tornado, Clinton, Oklahoma, October 12, 2021

This Unrated tornado ran 0.2 miles across Custer County on October 12, 2021, touching down at 8:01 PM CDT and reaching 20 yards wide. It killed nobody.

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 mph

    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. Unratedthis tornado

    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
Unrated
Date
October 12, 2021
Touchdown
8:01 PM CDT (01:01 UTC)
Path length
0.2 miles (0.3 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
County
Custer County
Touchdown point
35.531, -98.945
Lift-off point
35.531, -98.945
Record number
2110121901-01

The damage survey

7 damage points were recorded along this path by NWS OUN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 105 mph.

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

A warm front lifted north during the afternoon and evening of the 12th, with a couple supercells developing along it across southwest OK. Large hail, strong winds, and numerous tornadoes were reported with these storms as they moved northeastward. Later, a line of severe storms moved into far western OK along a cold front, with strong winds and hail reported with these storms.

A tornado developed on the east side of Clinton near First Street and Route 66 (Business 40) where it damaged a automobile body shop and damaged a warehouse building. The tornado moved northeast across Riverside Golf Course where trees were damaged, then damaged and destroyed hangars at Clinton Municipal Airport (CLK). After the damage at the Clinton Municipal Airport, the tornado moved through more rural areas but did continue to damage trees, blow the roof off at least one outbuilding (with the debris blown to the northwest) and blew a street sign 200 yards. At one point, storm chasers observed a satellite tornado adjacent to this tornado (see separate entry).

A number of storm chasers from various angles observed a second tornado adjacent to the tornado the moved from the east side of Clinton to southeast of Custer City. Although motion was difficult to determine at night, was believed to be a satellite tornado. This tornado produced no known damage and the location of this tornado was estimated.

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

The warnings

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 tornado watch, issued at 22:34 UTC and running to 04:00 UTC.

Issued (UTC)ExpiredProductOffice
22:34 UTC04:00 UTCTornado WatchOUN
23:14 UTC00:00 UTCSevere Thunderstorm WarningOUN
23:51 UTC00:15 UTCTornado WarningOUN
00:24 UTC01:15 UTCSevere Thunderstorm WarningOUN
01:02 UTC01:45 UTCTornado WarningOUN
01:41 UTC02:30 UTCSevere Thunderstorm WarningOUN
01:46 UTC02:15 UTCTornado WarningOUN
04:07 UTC09:49 UTCTornado WatchOUN
06:44 UTC07:30 UTCSevere Thunderstorm WarningOUN

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 Enhanced Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 00:33 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.

Norman, OK (KOUN), 00:00Z

1.0 hours before the tornado, 144 km from the path. October 13, 2021.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 00:00Z on 2021-10-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 496 joules per kilogram, CIN -164, lifted condensation level 662 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, Norman, OK at 00:00Z on 2021-10-13The 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 331 square meters per square second, 0 to 6 km bulk shear 58 knots.1939587897117Sfc1 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
496 J/kg
Mixed-layer CIN
-164 J/kg
Surface CAPE
198 J/kg
Mixed-layer LCL
662 m above ground
0-6 km bulk shear
58 kt
0-1 km bulk shear
35 kt
0-1 km storm-relative helicity
331 m²/s²
0-3 km storm-relative helicity
372 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.5
0-3 km lapse rate
4.9 K/km

Open this sounding in Storm Lab

The radar

The Altus AFB radar (KFDR), 130 km away, was scanning. The volume nearest the touchdown began at 01:00 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
00:25 UTCTSTM WND GST 771 Wnw Burns FlatWashita, OK
00:50 UTCTSTM WND DMGClintonCuster, OKROOF REMOVED FROM STRUCTURE ON EAST SIDE OF CLINTON. SEVERAL STUCTURES DAMAGED AT THE AIRPORT. TIME ESTIMATED BY RADAR.
00:53 UTCTSTM WND DMG4 Wsw ClintonCuster, OKSEMI TRUCK OVERTURNED ON I-40 NEAR EXIT 62
01:01 UTCTORNADO1 Sse ArapahoCuster, OKTIME AND LOCATION ESTIMATED BY RADAR

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 OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

The other tornadoes of October 12, 2021

20 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
October 126:48 PM CDTEF0Beckham, OK0.110
October 127:24 PM CDTUnratedWashita, OK0.125
October 126:25 PM MDTEF0Wallace, KS3.3100
October 127:38 PM CDTEF0Tillman, OK0.430
October 127:41 PM CDTEF1Tillman, OK7.3300$50,000
October 127:55 PM CDTEF1Custer, OK9.6400
October 128:19 PM CDTEF1Tillman, OK0.9300$5,000
October 128:26 PM CDTEF1Comanche, OK8.4900$15,000
October 129:00 PM CDTUnratedComanche, OK2.650
October 129:23 PM CDTEF1Haskell, KS12.9150
October 129:35 PM CDTUnratedCaddo, OK0.530
October 1210:02 PM CDTEF1Gray, KS1.975
October 1210:12 PM CDTEF1Ford, KS7.175
October 1210:39 PM CDTEF1Ford, KS10.775$110,000
October 1211:22 PM CDTEF1Ford, KS2.075
October 1211:38 PM CDTEF1Ford, KS0.950
October 1211:48 PM CDTUnratedKiowa, KS4.675
October 1211:49 PM CDTEF1Kiowa, KS3.575
October 1211:59 PM CDTEF1Edwards, KS6.3100
October 1212:05 AM CDTEF1Edwards, KS6.6100

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.