Tornadoes · United States · Oklahoma · 2021

EF1 tornado, Bidding Spgs to Baron, Oklahoma, April 28, 2021

From Bidding Spgs to Baron, this EF1 tornado ran 7.1 miles across Adair County on April 28, 2021, touching down at 6:06 AM CDT and reaching 225 yards wide. It killed nobody, and did $50,000 of property damage.

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 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.

The record

Rating
EF1
Date
April 28, 2021
Touchdown
6:06 AM CDT (11:06 UTC)
Lifted
6:19 AM CDT (11:19 UTC)
On the ground
13 minutes
Path length
7.1 miles (11.4 km)
Path width
225 yards (206 m)
Deaths
0
Injuries
0
Property damage
$50,000
County
Adair County
Touchdown point
35.836, -94.676
Lift-off point
35.902, -94.581
Record number
2104280506-01

The damage survey

10 damage points were recorded along this path by NWS TSA, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 97 mph.

  • Photo courtesy Adair County Emergency Management
  • Photo courtesy of Adair County Emergency Management

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

Strong to severe thunderstorms moved through eastern Oklahoma during the morning of the 28th. These storms produced locally heavy rainfall that resulted in flash flooding, damaging wind gusts, and three tornadoes. Another round of thunderstorms developed across eastern Oklahoma during the evening of the 28th, as a cold front moved into the area. The strongest storms produced damaging wind.||Widespread heavy rainfall of four to six inches, with isolated amounts to eight inches, resulted in significant rises on rivers in eastern Oklahoma. Major flooding occurred along the Illinois River, with moderate flooding along the Poteau River.

This tornado produced a tornadic debris signature on the KSRX WSR-88D that lasted at least three minutes. The survey team could not access the heavily wooded area where this tornado likely occurred due to the lack of roads transecting the path.

This tornado damaged a home, destroyed a couple outbuildings, damaged chicken houses, and uprooted trees. Based on this damage, maximum estimated wind in the tornado was 90 to 100 mph.

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

The warnings

14 minutes of warning. NWS TSA issued a tornado warning for this county at 10:52 UTC, 14 minutes before the tornado touched down, in force until 11:30 UTC.

The county was under a tornado watch, issued at 08:01 UTC and running to 15:00 UTC.

Issued (UTC)ExpiredProductOffice
05:00 UTC09:16 UTCFlood WatchTSA
08:01 UTC15:00 UTCTornado WatchTSA
10:52 UTC11:30 UTCTornado WarningTSA
11:26 UTC11:39 UTCTornado WarningTSA
11:45 UTC16:45 UTCFlood AdvisoryTSA
12:52 UTC17:45 UTCFlash Flood WarningTSA
13:29 UTC17:30 UTCFlash Flood WarningTSA
17:32 UTC02:30 UTCFlood WarningTSA
17:47 UTC07:03 UTCFlood WarningTSA
23:49 UTC13:29 UTCFlood WarningTSA
03:40 UTC07:45 UTCFlash Flood WarningTSA

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 05:53 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.

Springfield, MO (KSGF), 00:00Z

11.1 hours before the tornado, 137 km from the path. April 28, 2021.

Skew-T log-pSkew-T log-p diagram, Springfield, MO at 00:00Z on 2021-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 936 joules per kilogram, CIN -112, lifted condensation level 823 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, Springfield, MO at 00:00Z on 2021-04-28The 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 94 square meters per square second, 0 to 6 km bulk shear 34 knots.1939587897Sfc1 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
936 J/kg
Mixed-layer CIN
-112 J/kg
Surface CAPE
1026 J/kg
Mixed-layer LCL
823 m above ground
0-6 km bulk shear
34 kt
0-1 km bulk shear
22 kt
0-1 km storm-relative helicity
94 m²/s²
0-3 km storm-relative helicity
112 m²/s²
Significant tornado parameter
0.2
Supercell composite
0.5
0-3 km lapse rate
6.5 K/km

Open this sounding in Storm Lab

Springfield, MO (KSGF), 12:00Z

0.9 hours after it, 137 km from the path. April 28, 2021.

Skew-T log-pSkew-T log-p diagram, Springfield, MO at 12:00Z on 2021-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 34 joules per kilogram, CIN -105, lifted condensation level 1441 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, Springfield, MO at 12:00Z on 2021-04-28The 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 84 square meters per square second, 0 to 6 km bulk shear 41 knots.1939587897Sfc1 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
34 J/kg
Mixed-layer CIN
-105 J/kg
Surface CAPE
174 J/kg
Mixed-layer LCL
1441 m above ground
0-6 km bulk shear
41 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
127 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.3 K/km

Open this sounding in Storm Lab

The radar

The Western Arkansas radar (KSRX), 69 km away, was scanning. The volume nearest the touchdown began at 11:05 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
11:12 UTCTORNADO3 Nnw StilwellAdair, OKEF1 TORNADO UPROOTED TREES, DAMAGED AND DESTROYED SEVERAL BARNS. SEVERAL HOMES DAMAGED.
11:15 UTCTSTM WND DMG2 Nne MariettaAdair, OKLARGE BROKEN TREE LIMBS, DAMAGE TO POWER LINES, DAMAGE TO A BARN. POSSIBLE TORNADO. TIME ESTIMATED VIA RADAR.
12:09 UTCFLASH FLOODWestvilleAdair, OKVIDEO SENT VIA TWITTER OF FLOODED STREETS IN WESTVILLE.

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 April 28, 2021

10 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 286:01 AM CDTUnratedAdair, OK1.5100
April 289:30 AM CDTEF0Taney, MO0.150$25,000
April 289:37 AM CDTEF0Taney, MO0.650$125,000
April 289:55 AM CDTEF0Christian, MO0.450$5,000
April 2810:57 AM CDTEF1Pittsburg, OK7.4300$25,000
April 2811:13 AM CDTEF0Douglas, MO1.9100$250,000
April 282:50 PM CDTEF1Bollinger, MO3.4225
April 286:53 PM CDTEF1Henry, TN6.74001$600,000
April 287:33 PM CDTEF1Medina, TX1.8600$500,000
April 287:36 PM CDTUnratedColes, IL0.125

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.