Tornadoes · United States · South Dakota · 2021

Unrated tornado, Usta to Meadow, South Dakota, May 23, 2021

From Usta to Meadow, this Unrated tornado ran 4.3 miles across Perkins County on May 23, 2021, touching down at 3:58 PM MDT and reaching 10 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
May 23, 2021
Touchdown
3:58 PM MDT (21:58 UTC)
Lifted
4:05 PM MDT (22:05 UTC)
On the ground
7 minutes
Path length
4.3 miles (6.9 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Perkins County
Touchdown point
45.380, -102.220
Lift-off point
45.440, -102.240
Record number
2105231558-01

The damage survey

4 damage points were recorded along this path by NWS UNR, in the Damage Assessment Toolkit the survey teams carry.

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 supercell thunderstorm tracked northward across eastern Perkins County, producing strong wind gusts and two short-lived tornadoes. The tornadoes occurred over open prairie land and caused no damage.

A tornado formed west of SD Highway 73, about five miles north of Usta, and was on the ground for about five minutes. No damage was reported as it traveled over open terrain.

A tornado formed shortly after a previous tornado dissipated. This tornado touched down about ten miles south of Meadow and was on the ground for about seven minutes. No damage was reported as it traveled over open terrain.

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

The warnings

45 minutes of warning. NWS UNR issued a tornado warning for this county at 21:13 UTC, 45 minutes before the tornado touched down, in force until 22:00 UTC.

The county was under a tornado watch, issued at 19:51 UTC and running to 02:27 UTC.

Issued (UTC)ExpiredProductOffice
19:51 UTC02:27 UTCTornado WatchUNR
21:13 UTC22:00 UTCTornado WarningUNR
21:58 UTC22:45 UTCTornado WarningUNR

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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:53 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.

Rapid City, SD (KUNR), 12:00Z

10.0 hours before the tornado, 158 km from the path. May 23, 2021.

Skew-T log-pSkew-T log-p diagram, Rapid City, SD at 12:00Z on 2021-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -108264, lifted condensation level 549 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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, Rapid City, SD at 12:00Z on 2021-05-23The 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 271 square meters per square second, 0 to 6 km bulk shear 28 knots.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
-108264 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
549 m above ground
0-6 km bulk shear
28 kt
0-1 km bulk shear
36 kt
0-1 km storm-relative helicity
271 m²/s²
0-3 km storm-relative helicity
339 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.0 K/km

Open this sounding in Storm Lab

Rapid City, SD (KUNR), 00:00Z

2.0 hours after it, 158 km from the path. May 24, 2021.

Skew-T log-pSkew-T log-p diagram, Rapid City, SD at 00:00Z on 2021-05-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -2595, lifted condensation level 1290 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km-30°-20°-10°0°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, Rapid City, SD at 00:00Z on 2021-05-24The 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 -292 square meters per square second, 0 to 6 km bulk shear 67 knots.19395878Sfc1 km3 km6 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
0 J/kg
Mixed-layer CIN
-2595 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1290 m above ground
0-6 km bulk shear
67 kt
0-1 km bulk shear
21 kt
0-1 km storm-relative helicity
-292 m²/s²
0-3 km storm-relative helicity
-171 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.3 K/km

Open this sounding in Storm Lab

The surface observations

Faith (D07), 45 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:56 UTC7162120° 15 kt241010.5
21:56 UTC7562150° 19 kt311008.8
22:56 UTC7859160° 27 kt411007.5
23:56 UTC7658160° 20 kt371007.1

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

The radar

The Rapid City radar (KUDX), 151 km away, was scanning. The volume nearest the touchdown began at 21:56 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
21:35 UTCTSTM WND GST 608 Wnw UstaPerkins, SD
21:50 UTCTORNADO6 Nnw UstaPerkins, SDTORNADO OCCURRED IN OPEN GRASSLAND. NO DAMAGE REPORTED OR OBSERVED. EF UNKNOWN. PATH LENGTH 2.2 MILES.
21:52 UTCTORNADO23 Nnw FaithPerkins, SD
21:58 UTCTORNADO10 S MeadowPerkins, SDTORNADO OCCURRED IN OPEN GRASSLAND. NO DAMAGE REPORTED OR OBSERVED. EF UNKOWN. PATH LENGTH 3.8 MILES.
22:03 UTCTORNADO6 S MeadowPerkins, SD
00:40 UTCTSTM WND GST 661 Nne FaithMeade, SD
00:50 UTCTSTM WND GST 6010 Wsw Red ElmZiebach, SD
00:56 UTCTSTM WND GST 661 Nne FaithMeade, SD

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 South DakotaEvery tornado in South Dakota since 1950Warnings in force in South Dakota nowThe forecast where you are

The other tornadoes of May 23, 2021

11 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 232:00 PM MDTEF0Lincoln, CO0.025
May 232:24 PM MDTEF0Washington, CO0.025
May 232:52 PM MDTEF0Washington, CO0.725
May 233:14 PM MDTEF0Washington, CO0.025
May 233:49 PM MDTEF1Logan, CO0.150
May 233:50 PM MDTUnratedPerkins, SD2.110
May 233:55 PM MDTEF1Custer, SD6.620
May 234:04 PM MDTEF1Custer, SD5.910
May 234:19 PM MDTEF0Logan, CO0.025
May 234:29 PM MDTEF1Logan, CO0.150
May 234:45 PM MDTEF0Lincoln, CO0.525

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.