Tornadoes · United States · Oklahoma · 2021

Unrated tornado, Indiahoma to Meers, Oklahoma, October 12, 2021

From Indiahoma to Meers, this Unrated tornado ran 2.6 miles across Comanche County on October 12, 2021, touching down at 9:00 PM CDT and reaching 50 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
9:00 PM CDT (02:00 UTC)
Lifted
9:07 PM CDT (02:07 UTC)
On the ground
7 minutes
Path length
2.6 miles (4.2 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Comanche County
Touchdown point
34.778, -98.685
Lift-off point
34.803, -98.661
Record number
2110122000-01

The damage survey

21 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 108 mph.

  • Car port attached to barn destroyed
  • We think this door is from this event
  • SN report of power lines down on SH-19 trapping people in cars. Other report of metal barn "blown apart" somewhere in area.
  • Likely location of house damage seen in tweet.

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.

This tornado moved into Comanche County from Kiowa County approximately three miles north of U.S. Highway 62, and moved northeast and then due north. At least one home suffered some shingle damage, a mobile home received roof damage, and a barn door was blown in. Tree damage was also observed along the path. None of the damage in Comanche County was observed to be greater than EF0, although the tornado was likely stronger as there were few damage indicators encountered along the path.

Radar indicated strong rotation with a tornado debris signature in an inaccessible area of the Wichita Mountains. The path and path dimensions are estimated.

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

The warnings

48 minutes of warning. NWS OUN issued a tornado warning for this county at 01:12 UTC, 48 minutes before the tornado touched down, in force until 02:00 UTC.

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
00:40 UTC00:55 UTCTornado WarningOUN
01:12 UTC02:00 UTCTornado WarningOUN
01:53 UTC02:27 UTCTornado 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. 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

2.0 hours before the tornado, 125 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), 55 km away, was scanning. The volume nearest the touchdown began at 02:00 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
00:39 UTCTORNADO2 Ssw FrederickTillman, OK
01:21 UTCHAIL 1.755 S SnyderTillman, OK
02:40 UTCTSTM WND GST 584 Nnw Fort CobbCaddo, OK

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 128:01 PM CDTUnratedCuster, OK0.220
October 128:19 PM CDTEF1Tillman, OK0.9300$5,000
October 128:26 PM CDTEF1Comanche, OK8.4900$15,000
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.