Tornadoes · United States · Colorado · 2015

EF0 tornado, Firstview, Colorado, May 9, 2015

This EF0 tornado ran 1.0 miles across Cheyenne County on May 9, 2015, touching down at 5:35 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 9, 2015
Touchdown
5:35 PM MDT (23:35 UTC)
Lifted
5:38 PM MDT (23:38 UTC)
On the ground
3 minutes
Path length
1.0 miles (1.7 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Cheyenne County
Touchdown point
38.783, -102.512
Lift-off point
38.798, -102.518
Record number
1505091735-01

What the Weather Service recorded

A supercell thunderstorm moved north from Kiowa into Cheyenne County producing several large tornadoes. No damage was reported with the tornadoes remaining over open country.

A large tornado crossed from Kiowa County into southern Cheyenne County.

An intermittent needle tornado reached the ground four times over the course of several minutes. no damage was observed.

Tornado on the ground intermittently, with no damage reported.

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

The warnings

27 minutes of warning. NWS GLD issued a tornado warning for this county at 23:08 UTC, 27 minutes before the tornado touched down, in force until 00:00 UTC.

The county was under a tornado watch, issued at 17:55 UTC and running to 02:32 UTC.

Issued (UTC)ExpiredProductOffice
17:55 UTC02:32 UTCTornado WatchGLD
22:38 UTC23:15 UTCTornado WarningGLD
23:08 UTC00:00 UTCTornado WarningGLD
23:50 UTC00:17 UTCTornado WarningGLD
00:16 UTC00:25 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 Enhanced Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 20:04 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 (KDEN), 12:00Z

11.6 hours before the tornado, 135 km from the path. May 9, 2015.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2015-05-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 53 joules per kilogram, CIN -132, lifted condensation level 660 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 12:00Z on 2015-05-09The 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 49 square meters per square second, 0 to 6 km bulk shear 59 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
53 J/kg
Mixed-layer CIN
-132 J/kg
Surface CAPE
72 J/kg
Mixed-layer LCL
660 m above ground
0-6 km bulk shear
59 kt
0-1 km bulk shear
8 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
196 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
6.0 K/km

Open this sounding in Storm Lab

The surface observations

Burlington (ITR), 54 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:53 UTC6250130° 16 kt231007.1
22:53 UTC6351130° 10 kt1007.1
23:17 UTC4943350° 18 kt271007.8
23:41 UTC474210° 17 kt241007.8
23:46 UTC474210° 20 kt251007.5
23:53 UTC4642360° 18 kt251007.5
00:08 UTC4642360° 19 kt301007.1TS
00:46 UTC4340350° 19 kt321006.8+TSRA BR
00:53 UTC4239360° 21 kt301006.4+TSRA BR
00:57 UTC4239360° 26 kt371006.1-TSRA BR
01:08 UTC423910° 19 kt331006.8VCTS
01:25 UTC423910° 16 kt211006.8TS

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

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
21:01 UTCTORNADO13 Ne EadsCheyenne, COSPOTTER CONFIRMED TORNADO ON THE GROUND.
22:25 UTCHAIL 1.253 Ese EadsKiowa, COMOSTLY QUARTER ... SOME HALF DOLLAR SIZED HAIL.
22:27 UTCTORNADO6 Se EadsKiowa, CO
23:01 UTCTORNADO13 Ne EadsCheyenne, COSPOTTER CONFIRMED TORNADO ON THE GROUND.
23:10 UTCTORNADO12 Ssw FirstviewCheyenne, COTORNADO PICKED UP AND TOUCHED BACK DOWN.
23:20 UTCTORNADO5 Se Kit CarsonCheyenne, COTORNADO ON THE GROUND.
23:20 UTCTORNADO7 S FirstviewCheyenne, COTORNADO ON THE GROUND.
23:24 UTCTORNADO6 S FirstviewCheyenne, COTORNADO BACK ON THE GROUND. BRIEF TORNADO LIFTED AND ANOTHER TORNADO TOUCHED DOWN IMMEDIATELY AFTERWARDS.
23:26 UTCHAIL 22 E FirstviewCheyenne, CO
23:35 UTCTORNADO2 Sse FirstviewCheyenne, COTORNADO ON THE GROUND INTERMITTENTLY.
00:14 UTCHAIL 116 S BurlingtonKit Carson, COSPOTTER REPORT OF NICKEL TO QUARTER SIZED HAIL.
00:30 UTCHAIL 110 S BurlingtonKit Carson, CO
00:52 UTCHAIL 1.253 S BurlingtonKit Carson, COSTORM SPOTTER REPORT OF 1.25 INCH HAIL COVERING THE ROAD.

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

This ground now

The live radar over the trackEvery 2015 tornado in ColoradoEvery tornado in Colorado since 1950Warnings in force in Colorado nowThe forecast where you are

The other tornadoes of May 9, 2015

28 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 94:32 PM CDTEF3Eastland, TX3.81,40012$300,000
May 93:40 PM MDTEF0Lincoln, CO0.050
May 93:41 PM MDTEF0El Paso, CO3.3100
May 94:55 PM CDTEF0Cooke, TX0.740
May 95:15 PM CDTEF0Eastland, TX0.120$90,000
May 94:27 PM MDTEF0Kiowa, CO1.150
May 94:30 PM MDTEF0Elbert, CO0.150
May 95:30 PM CDTEF0Love, OK0.330
May 94:40 PM MDTEF0Elbert, CO0.150
May 95:50 PM CDTEF0Love, OK0.330
May 94:50 PM MDTEF0Kiowa, CO11.1150$3,000
May 95:57 PM CDTEF0Wichita, TX3.350
May 96:09 PM CDTEF0Cotton, OK1.0100
May 95:20 PM MDTEF0Cheyenne, CO2.110
May 96:24 PM CDTEF0Marshall, OK3.0200
May 96:58 PM CDTEF0Erath, TX0.380
May 97:25 PM CDTEF1Bryan, OK5.3200
May 97:28 PM CDTEF0Trego, KS4.0100
May 97:55 PM CDTEF0Graham, KS2.850
May 98:00 PM CDTEF0Gove, KS5.7100
May 98:24 PM CDTEF0Roger Mills, OK2.0100
May 98:25 PM CDTEF0Harlan, NE0.315
May 98:36 PM CDTEF0Harlan, NE0.015
May 98:38 PM CDTEF1Gove, KS6.150$50,000
May 99:12 PM CDTEF0Sheridan, KS13.9150
May 99:50 PM CDTEF2Sheridan, KS18.8150$75,000
May 910:43 PM CDTEF1Decatur, KS11.750$6,000
May 911:20 PM CDTEF0Red Willow, NE4.225

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.