Tornadoes · United States · Oklahoma · 2015

EF3 tornado, Amber to Bridge Creek, Oklahoma, May 6, 2015

From Amber to Bridge Creek, this EF3 tornado ran 10.3 miles across Grady County on May 6, 2015, touching down at 4:33 PM CDT and reaching 1,500 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 mphthis tornado

    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
EF3
Date
May 6, 2015
Touchdown
4:33 PM CDT (21:33 UTC)
Lifted
5:26 PM CDT (22:26 UTC)
On the ground
53 minutes
Path length
10.3 miles (16.6 km)
Path width
1,500 yards (1372 m)
Deaths
0
Injuries
0
County
Grady County
Touchdown point
35.158, -97.803
Lift-off point
35.266, -97.698
Record number
1505061533-01

The damage survey

312 damage points were recorded along this path by NWS OUN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF3. The highest wind the damage implies is 149 mph.

  • 100 yard length of livestock fence pulled to the north, 1 pole snapped.
  • Two signs, tree and fence block (hollow) bent to the southwest. vortex south of here probable based on damage direction.
  • 4 signs blown down to the north.
  • Wood power pole snapped, leaning north.

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 potent Spring storm system took shape across the Southern and Central Plains. Strong surface cyclogenesis took shape during the day, allowing ample moisture to return northward with strong southerly flow. At the same time, a strong upper level shortwave trough allowed strong mid level westerlies to overspread much of the Plains region. With large instability and wind shear, the stage was set for widespread severe storm development. Storms initiated within the open warm sector ahead of the dryline. The first storm developed near Lawton and moved northeast along I-44 into parts of central Oklahoma, resulting in several tornadoes and large hail. Additional supercells spawned tornadoes across northern Oklahoma, and the slow moving nature of storms lead to several occurrences of flash flooding. Storms continued well into the night.

A large tornado developed east of Amber and moved slowly northeast near or along Interstate 44, then turned north impacting the community of Bridge Creek. The most intense damage occurred just east of the Interstate 44 and H.E. Bailey Turnpike Spur near Bridge Creek where EF3 damage was observed to a home (DI 2, DOD 7) and a mobile home (DI 4, DOD 12). A pickup truck was also thrown for several hundred yards in this area. Numerous homes and other buildings were damaged along the tornado path.

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

The warnings

21 minutes of warning. NWS OUN issued a tornado warning for this county at 21:12 UTC, 21 minutes before the tornado touched down, in force until 21:45 UTC.

The county was under a tornado watch, issued at 18:25 UTC and running to 01:51 UTC.

Issued (UTC)ExpiredProductOffice
04:41 UTC07:45 UTCFlash Flood WarningOUN
05:27 UTC05:58 UTCSevere Thunderstorm WarningOUN
07:11 UTC10:15 UTCFlood AdvisoryOUN
18:25 UTC01:51 UTCTornado WatchOUN
20:10 UTC20:45 UTCTornado WarningOUN
20:43 UTC21:15 UTCTornado WarningOUN
21:12 UTC21:45 UTCTornado WarningOUN
21:43 UTC22:30 UTCTornado WarningOUN
22:21 UTC23:00 UTCSevere Thunderstorm WarningOUN
22:25 UTC22:34 UTCTornado WarningOUN
23:06 UTC14:00 UTCFlash Flood WarningOUN
23:12 UTC00:00 UTCSevere Thunderstorm WarningOUN
23:31 UTC00:00 UTCTornado WarningOUN
23:57 UTC00:30 UTCTornado WarningOUN
00:02 UTC00:45 UTCSevere Thunderstorm WarningOUN
00:09 UTC01:00 UTCSevere Thunderstorm WarningOUN
00:25 UTC01:00 UTCTornado WarningOUN
00:29 UTC01:00 UTCSevere Thunderstorm WarningOUN
00:45 UTC01:30 UTCSevere Thunderstorm WarningOUN
00:59 UTC01:45 UTCTornado WarningOUN
01:04 UTC01:45 UTCSevere Thunderstorm WarningOUN
01:14 UTC02:00 UTCSevere Thunderstorm WarningOUN
01:28 UTC02:00 UTCTornado WarningOUN
01:34 UTC02:15 UTCSevere Thunderstorm WarningOUN
01:51 UTC06:31 UTCTornado WatchOUN

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 20:00 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.

Norman, OK (KOUN), 12:00Z

9.6 hours before the tornado, 32 km from the path. May 6, 2015.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2015-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1226 joules per kilogram, CIN -16, lifted condensation level 562 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, Norman, OK at 12:00Z on 2015-05-06The 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 219 square meters per square second, 0 to 6 km bulk shear 27 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
1226 J/kg
Mixed-layer CIN
-16 J/kg
Surface CAPE
1997 J/kg
Mixed-layer LCL
562 m above ground
0-6 km bulk shear
27 kt
0-1 km bulk shear
32 kt
0-1 km storm-relative helicity
219 m²/s²
0-3 km storm-relative helicity
308 m²/s²
Significant tornado parameter
1.2
Supercell composite
9.1
0-3 km lapse rate
6.6 K/km

Open this sounding in Storm Lab

Norman, OK (KOUN), 00:00Z

2.4 hours after it, 32 km from the path. May 7, 2015.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 00:00Z on 2015-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1821 joules per kilogram, CIN -7, lifted condensation level 916 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 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, Norman, OK at 00:00Z on 2015-05-07The 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 246 square meters per square second, 0 to 6 km bulk shear 36 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
1821 J/kg
Mixed-layer CIN
-7 J/kg
Surface CAPE
2793 J/kg
Mixed-layer LCL
916 m above ground
0-6 km bulk shear
36 kt
0-1 km bulk shear
29 kt
0-1 km storm-relative helicity
246 m²/s²
0-3 km storm-relative helicity
343 m²/s²
Significant tornado parameter
3.0
Supercell composite
19.3
0-3 km lapse rate
6.8 K/km

Open this sounding in Storm Lab

The surface observations

Chickasha Municipal Airport (CHK), 23 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:35 UTC73.468170° 14 kt201010.5
19:55 UTC73.468160° 14 kt201010.5-RA
20:15 UTC71.669.8160° 13 kt1010.2RA
20:35 UTC71.669.8110° 7 kt1010.2+RA
20:55 UTC69.868340° 21 kt241008.8+RA
21:15 UTC6864.440° 15 kt421008.8
21:35 UTC6862.6330° 23 kt301009.1
21:55 UTC6862.650° 7 kt1008.8
22:15 UTC71.668130° 9 kt181008.5
22:35 UTC6864.4130° 10 kt1007.5
22:55 UTC73.469.8140° 14 kt1007.8
23:15 UTC73.469.8140° 10 kt1007.1

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

The radar

The Norman radar (KTLX), 45 km away, was scanning. The volume nearest the touchdown began at 21:31 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
19:42 UTCTORNADO3 E ApacheCaddo, OKSTORM CHASER REPORTED A TORNADO DEVELOPED ABOUT 242 PM 2.5 MILES EAST OF APACHE AND MOVED NORTHEAST.
19:45 UTCTSTM WND DMG3 S SteckerCaddo, OKTREE LIMBS LARGER THAN 2 INCHES IN DIAMETER DOWNED BY WINDS.
19:53 UTCTORNADO4 Nw CyrilCaddo, OK
20:05 UTCHAIL 16 S AnadarkoCaddo, OK
20:12 UTCHAIL 26 S VerdenGrady, OK
20:16 UTCHAIL 1.53 S AnadarkoCaddo, OK
20:23 UTCHAIL 1.5VerdenGrady, OK
21:33 UTCTORNADO3 E AmberGrady, OK
21:33 UTCTORNADO4 E AmberGrady, OKUPDATED. EF3 TORNADO MOVED FROM 4.5 MILES EAST OF AMBER TO BRIDGE CREEK TO 4 MILES NORTH-NORTHEAST OF BRIDGE CREEK AROUND 526 PM. MANY STRUCTURES WERE DAMAGED OR DESTROYED.
22:33 UTCTORNADO2 Se NewcastleMcclain, OKEF1 TORNADO. TWO OUTBUILDINGS WERE DESTROYED AND TREES WERE DAMAGED IN SOUTHEAST NEWCASTLE.
22:46 UTCTORNADO4 Wnw NormanCleveland, OKBRIEF TOUCHDOWN AT THE INTERSECTION OF 48TH AND ROBINSON.
22:46 UTCTORNADO4 Wnw NormanCleveland, OKUPDATED. EF0 TORNADO. BRIEF TOUCHDOWN AT THE INTERSECTION OF NORTHWEST 60TH AND ROBINSON.
22:51 UTCTSTM WND GST 705 Wnw NormanCleveland, OKROTATING WALL CLOUD REPORTED AS WELL.
22:53 UTCTORNADO4 Nw NormanCleveland, OKUPDATED. EF1 TORNADO. TORNADO BEGAN JUST SOUTH OF NORTHWEST 36TH AVENUE AND ROCK CREEK ROAD AND MOVED GENERALLY NORTH THROUGH WEST NORMAN TO NEAR NORTHWEST 36TH AVENUE AND INDIAN HILLS ROAD AT AROUND 610 PM.
22:55 UTCHAIL 17 E AnadarkoCaddo, OK
23:00 UTCTSTM WND DMG3 Wnw NormanCleveland, OKDAMAGE TO A HOTEL AT INTERSTATE 35 AND ROBINSON STREET.
23:00 UTCTORNADO4 Nw NormanCleveland, OKTORNADO WITH DAMAGE IN NORTHWEST NORMAN... NEAR NORTHWEST 36TH AVENUE AND TECUMSEH ROAD AND NEARBY AREAS.
23:04 UTCHAIL 17 W AnadarkoCaddo, OK
23:10 UTCTSTM WND GST 582 Nw NormanCleveland, OK
23:13 UTCFLASH FLOODNewcastleMcclain, OKNUMEROUS ROADS AND DITCHES FLOODED NEAR HWY 62.
23:30 UTCHAIL 1.75TuttleGrady, OKDAMAGE TO CARS AND SIDING... ONE WINDOW IN HOME BROKEN.
23:45 UTCTORNADO5 Nnw VerdenCaddo, OKUPDATED LOCATION.
23:45 UTCTORNADO5 N VerdenGrady, OK
23:56 UTCFLASH FLOOD1 S MooreCleveland, OK19TH STREET IS IMPASSABLE DUE TO VERY HIGH WATER UNDER THE RAILROAD OVERPASS.
00:12 UTCFLASH FLOOD3 Nnw Warr AcresOklahoma, OKSTRANDED VEHICLES DUE TO HIGH WATER AND EXCESSIVE RAINFALL

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 OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

The other tornadoes of May 6, 2015

47 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 62:58 AM CDTEF0Creek, OK1.5100
May 62:24 PM CDTEF0Lincoln, KS10.7100$25,000
May 62:45 PM CDTEF0Caddo, OK2.050
May 62:53 PM CDTEF0Caddo, OK0.550
May 63:31 PM CDTEF0Jewell, KS1.025
May 63:55 PM CDTEF2Jewell, KS12.63501$1.5 million
May 64:18 PM CDTEF1Adams, NE3.9300$1.5 million
May 64:37 PM CDTEF0Major, OK0.120
May 64:38 PM CDTEF1Nuckolls, NE9.5200$250,000
May 64:48 PM CDTEF0Grady, OK to KS, NE0.350
May 64:48 PM CDTEF2Nuckolls, KS to NE20.1400$4.3 million
May 64:49 PM CDTEF3Sedgwick, KS16.53001$630,000
May 64:54 PM CDTEF1Jewell, KS4.3250$250,000
May 65:04 PM CDTEF1Jewell, KS3.160$5,000
May 65:08 PM CDTEF1Republic, KS2.175
May 65:10 PM CDTEF0Republic, KS3.150
May 65:15 PM CDTEF0Garfield, OK0.110
May 65:20 PM CDTEF2Republic, KS to NE36.2800$1.0 million
May 65:26 PM CDTEF0Thayer, NE1.8100$500,000
May 65:28 PM CDTEF0Thayer, NE1.030
May 65:33 PM CDTEF1McClain, OK1.0200
May 65:38 PM CDTEF0Sedgwick, KS0.350
May 65:45 PM CDTEF0Hall, NE0.025
May 65:46 PM CDTEF0Cleveland, OK0.525
May 65:53 PM CDTEF1Cleveland, OK3.31,000
May 66:33 PM CDTEF0Dewey, OK0.330
May 66:41 PM CDTEF0Caddo, OK3.5200
May 66:56 PM CDTEF0Grant, OK0.320
May 67:14 PM CDTEF3Republic, KS1.9100
May 67:28 PM CDTEF0Republic, KS0.050
May 67:35 PM CDTEF0Harper, KS0.350
May 67:38 PM CDTEF1Republic, KS2.475
May 67:49 PM CDTEF0Grady, OK0.540
May 68:11 PM CDTEF0Grady, OK3.5200
May 68:33 PM CDTEF0Cloud, KS0.375
May 68:38 PM CDTEF0Ottawa, KS0.050
May 68:41 PM CDTEF3Oklahoma, OK2.070012
May 68:49 PM CDTEF2Archer, TX12.0400
May 68:55 PM CDTEF0Ottawa, KS0.350
May 69:10 PM CDTEF0Washington, KS6.050
May 69:27 PM CDTEF0Cloud, KS8.875
May 69:37 PM CDTEF0Throckmorton, TX3.4440
May 69:56 PM CDTEF1Washington, KS4.075
May 610:00 PM CDTEF0Throckmorton, TX1.2100
May 610:36 PM CDTEF0Washington, KS0.375
May 610:49 PM CDTEF1Gage, NE7.7500
May 611:00 PM CDTEF0Throckmorton, TX0.050

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.