Tornadoes · United States · Wyoming · 2014

EF0 tornado, Dwyer Junction, Wyoming, May 21, 2014

This EF0 tornado ran 0.9 miles across Platte County on May 21, 2014, touching down at 7:15 PM MDT and reaching 25 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 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.

The record

Rating
EF0
Date
May 21, 2014
Touchdown
7:15 PM MDT (01:15 UTC)
Lifted
7:20 PM MDT (01:20 UTC)
On the ground
5 minutes
Path length
0.9 miles (1.5 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Platte County
Touchdown point
42.202, -105.005
Lift-off point
42.210, -104.990
Record number
1405211915-01

What the Weather Service recorded

Thunderstorms produced large hail, torrential rainfall, funnel clouds and a tornado across portions of east-central and southeast Wyoming.

A weak tornado initially touched down just east of Interstate 25 mile marker 90 north of Wheatland. The tornado lifted and touched down for five minutes before it dissipated. No damage was reported.

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

The warnings

17 minutes of warning. NWS CYS issued a tornado warning for this county at 00:58 UTC, 17 minutes before the tornado touched down, in force until 01:25 UTC.

The county was under a tornado watch, issued at 18:42 UTC and running to 02:25 UTC.

Issued (UTC)ExpiredProductOffice
18:42 UTC02:25 UTCTornado WatchCYS
23:38 UTC05:30 UTCFlash Flood WarningCYS
00:58 UTC01:25 UTCTornado WarningCYS
01:48 UTC02:15 UTCTornado WarningCYS
02:04 UTC06:00 UTCFlash Flood WarningCYS
05:23 UTC11:18 UTCFlood WarningCYS
18:34 UTC23:58 UTCSevere Thunderstorm WatchCYS

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 General Thunderstorms Risk. The outlook in force was issued at 01:00 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 (KRAP), 00:00Z

1.3 hours before the tornado, 269 km from the path. May 22, 2014.

Skew-T log-pSkew-T log-p diagram, Rapid City, SD at 00:00Z on 2014-05-22Temperature 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 -77199, lifted condensation level 1024 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 00:00Z on 2014-05-22The 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 139 square meters per square second, 0 to 6 km bulk shear 37 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
-77199 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1024 m above ground
0-6 km bulk shear
37 kt
0-1 km bulk shear
20 kt
0-1 km storm-relative helicity
139 m²/s²
0-3 km storm-relative helicity
252 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.6 K/km

Open this sounding in Storm Lab

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

10.7 hours after it, 269 km from the path. May 22, 2014.

Skew-T log-pSkew-T log-p diagram, Rapid City, SD at 12:00Z on 2014-05-22Temperature 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 -90653, lifted condensation level 1035 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 2014-05-22The 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 76 square meters per square second, 0 to 6 km bulk shear 21 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
-90653 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1035 m above ground
0-6 km bulk shear
21 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
76 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.5 K/km

Open this sounding in Storm Lab

The radar

The Cheyenne radar (KCYS), 118 km away, was scanning. The volume nearest the touchdown began at 01:12 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
23:40 UTCHAIL 0.2511 Nw WheatlandPlatte, WY
01:02 UTCFUNNEL CLOUD11 N WheatlandPlatte, WY
01:15 UTCTORNADO14 N WheatlandPlatte, WYNEAR MM 90 ON INTERSTATE 25. SEVERAL PHOTOS TAKEN.
01:15 UTCTORNADO14 N WheatlandPlatte, WYSEPARATE PHOTO OF TORNADO NEAR MILE MARKER 90 ON INTERSTATE 25. TORNADO LIFTED AND TOUCHED DOWN 4 TIMES.
01:20 UTCHAIL 1GuernseyPlatte, WY
02:31 UTCFLASH FLOODWheatlandPlatte, WY8 MI WEST OF GUERNSEY HWY 26 IS CLOSED DUE TO FLOODING. 40 FT OF THE ROAD IS UNDER WATER.
02:41 UTCFLASH FLOOD13 N WheatlandPlatte, WYI-25 AT MILE MARKER 94. ROAD FLOODED AT CONSTRUCTION DETOUR.
04:00 UTCFLASH FLOODGuernseyPlatte, WYNUMEROUS ROADS HAVE BEEN WASHED OUT AND REMAIN CLOSED BETWEEN WHEATLAND AND GUERNSEY. THESE ROADS INCLUDE LUCINDA RAWLINS...EAST JOHNSON TO HIGHWAY 320...WENDOVER ROAD...COTTONWOOD ROAD...NORTH DWYER ROAD AND BADGER ROAD

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2014 tornado in WyomingEvery tornado in Wyoming since 1950Warnings in force in Wyoming nowThe forecast where you are

The other tornadoes of May 21, 2014

9 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 2112:38 PM PDTEF0Elko, NV0.225
May 2112:48 PM PDTEF0Elko, NV0.3125$2,000
May 212:05 PM MDTEF0Arapahoe, CO0.150
May 212:30 PM MDTEF0Adams, CO0.150
May 212:45 PM MDTEF0Adams, CO0.150
May 214:20 PM MDTEF0Arapahoe, CO0.150
May 215:06 PM MDTEF0Adams, CO0.150
May 214:30 PM PDTEF0Lander, NV0.250
May 216:40 PM MDTEF0Power, ID3.020$1,000

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.