Tornadoes · United States · Colorado · 2021

Unrated tornado, Firstview, Colorado, April 27, 2021

This Unrated tornado ran 1.9 miles across Cheyenne County on April 27, 2021, touching down at 5:27 PM MDT and reaching 75 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
April 27, 2021
Touchdown
5:27 PM MDT (23:27 UTC)
Lifted
5:34 PM MDT (23:34 UTC)
On the ground
7 minutes
Path length
1.9 miles (3.1 km)
Path width
75 yards (69 m)
Deaths
0
Injuries
0
County
Cheyenne County
Touchdown point
38.954, -102.609
Lift-off point
38.981, -102.618
Record number
2104271727-01

What the Weather Service recorded

A frontal boundary slowly pushed north across eastern Colorado during the afternoon hours before shifting east into western Kansas and extreme southwest Nebraska during the evening hours. Storms formed along and north of the front and moved across eastern Colorado producing tornadoes, up to golf ball sized hail, and up to 60 mph wind gusts.

Landspout tornado, multiple reports received along with video of tornado near the intersection of county roads DD and 32 in northern Cheyenne County.

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 severe thunderstorm watch, issued at 17:47 UTC and running to 01:00 UTC.

Issued (UTC)ExpiredProductOffice
17:47 UTC01:00 UTCSevere Thunderstorm WatchGLD
22:03 UTC23:00 UTCSevere Thunderstorm WarningGLD
22:06 UTC22:30 UTCTornado WarningGLD
22:31 UTC23:00 UTCTornado WarningGLD
23:02 UTC23:34 UTCSevere Thunderstorm WarningGLD

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 Marginal Risk. The outlook in force was issued at 19:49 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.

Denver, CO (KDNR), 12:00Z

11.5 hours before the tornado, 113 km from the path. April 27, 2021.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2021-04-27Temperature 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 -82987, lifted condensation level 3214 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 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, Denver, CO at 12:00Z on 2021-04-27The 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 51 square meters per square second, 0 to 6 km bulk shear 67 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
0 J/kg
Mixed-layer CIN
-82987 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3214 m above ground
0-6 km bulk shear
67 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
7.1 K/km

Open this sounding in Storm Lab

Denver, CO (KDNR), 00:00Z

0.5 hours after it, 113 km from the path. April 28, 2021.

Skew-T log-pSkew-T log-p diagram, Denver, CO 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 26 joules per kilogram, CIN -21, lifted condensation level 1024 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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, Denver, CO 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 -2 square meters per square second, 0 to 6 km bulk shear 42 knots.193958Sfc1 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
26 J/kg
Mixed-layer CIN
-21 J/kg
Surface CAPE
327 J/kg
Mixed-layer LCL
1024 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
1 kt
0-1 km storm-relative helicity
-2 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.0
0-3 km lapse rate
8.2 K/km

Open this sounding in Storm Lab

The radar

The Goodland radar (KGLD), 90 km away, was scanning. The volume nearest the touchdown began at 23:29 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
22:10 UTCTORNADO14 Ssw Wild HorseCheyenne, COCORRECTS PREVIOUS TORNADO REPORT FROM 14 SSW WILD HORSE. DELAYED REPORT. CHEYENNE COUNTY SHERIFF REPORTED 3 TORNADOES WITH WALL CLOUDS. ADDITIONAL REPORTS RECEIVED FROM SPOTTERS LOOKING AT STORM FROM A LOCATION NORTH OF
22:10 UTCTORNADO14 Ssw Wild HorseCheyenne, CODELAYED REPORT. CHEYENNE COUNTY SHERIFF REPORTED 3 TORNADOES WITH WALL CLOUDS.
22:28 UTCHAIL 0.8815 S FlaglerKit Carson, COPEA TO NICKEL SIZED HAIL.
22:33 UTCTORNADO10 S Wild HorseCheyenne, CODELAYED REPORT. TORNADOES VIEWED ON LIVE CHASER STREAM.
22:55 UTCTSTM WND GST 6010 Ssw KirkKit Carson, COCALLER REPORTED E60 MPH WINDS AND PEA SIZED HAIL.
22:56 UTCTORNADO2 W Kit CarsonCheyenne, CODELAYED REPORT VIA SOCIAL MEDIA. VIDEO OF A TORNADO CROSSED US-40.
23:03 UTCTSTM WND GST 603 Se Kit CarsonCheyenne, COTRAINED SPOTTER REPORTED 60 MPH WINDS THAT LASTED 2 MINUTES IN DURATION.
23:04 UTCHAIL 1.7516 S StrattonKit Carson, COCALLER REPORTED ESTIMATED PING PONG TO GOLF BALL HAIL. OVER A DURATION OF 4 MINUTES THE HAIL BECAME SMALLER AND HEAVIER.
23:33 UTCTORNADO13 N FirstviewCheyenne, CODELAYED REPORT. MULTIPLE REPORTS RECEIVED ALONG WITH VIDEO OF A TORNADO NEAR THE INTERSECTION OF COUNTY RD DD AND 32.

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 ColoradoEvery tornado in Colorado since 1950Warnings in force in Colorado nowThe forecast where you are

The other tornadoes of April 27, 2021

13 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 272:32 PM MDTEF0Lincoln, CO0.050
April 273:49 PM CDTEF3Knox, TX8.4400$70,000
April 273:57 PM MDTEF0Lincoln, CO0.050
April 274:08 PM MDTUnratedCheyenne, CO0.850
April 274:08 PM MDTUnratedCheyenne, CO2.0100
April 274:15 PM MDTUnratedCheyenne, CO2.075
April 274:16 PM MDTUnratedCheyenne, CO4.0300
April 274:28 PM MDTUnratedCheyenne, CO1.3100
April 274:54 PM MDTUnratedCheyenne, CO4.550
April 277:15 PM CDTEF0Tillman, OK0.120
April 277:19 PM CDTUnratedWilbarger, TX0.230
April 277:47 PM CDTEF0Scurry, TX2.650
April 2712:00 AM CDTEF1Garvin, OK4.5150$30,000

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.