Tornadoes · United States · Oklahoma · 2010

EF1 tornado, Hennepin to Sulphur, Oklahoma, May 19, 2010

From Hennepin to Sulphur, this EF1 tornado ran 17.5 miles across Garvin and Murray counties on May 19, 2010, touching down at 8:31 PM CDT and reaching 375 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 mphthis tornado

    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
EF1
Date
May 19, 2010
Touchdown
8:31 PM CDT (01:31 UTC)
Lifted
8:53 PM CDT (01:53 UTC)
On the ground
22 minutes
Path length
17.5 miles (28.2 km)
Path width
375 yards (343 m)
Deaths
0
Injuries
0
Counties
Garvin and Murray counties
Touchdown point
34.578, -97.268
Lift-off point
34.626, -96.970
Record number
1005191931-01

What the Weather Service recorded

A large storm system moved through the southern and central Plains during the morning and afternoon of the 19th. Thunderstorms, some of them severe, had developed over the Texas panhandle and moved east into northwest and north central Oklahoma during the early morning hours. Additional development, aided by the low-level jet, occurred into parts of central Oklahoma, north of a warm front that was slowly moving north to near Interstate 40. ||By mid afternoon, the well-defined front was located from parts of west-central into central Oklahoma, just north of the Oklahoma City metro area. Two thunderstorms developed near and along the front, one over Roger Mills and Dewey counties, and the other over northern Blaine county. The storms quickly became tornadic, with the first tornado of the day occurring north of Leedey in Dewey county. Another tornado, and probably the most photographed one of the day, occurred just north of Hennessey. Tornadoes, most of them brief in duration, and large hail continued across western and central Kingfisher county, and across northern Logan, southeast Garfield, and Payne counties. Another thunderstorm developed further east along the dry line later in the afternoon, and the storm eventually produced a tornado west of Prague in Lincoln county. ||Finally, two supercell thunderstorms developed further south along the dry line that moved into central Oklahoma. Although both showed significant rotation on radar, only the supercell that moved from Stephens through Murray counties produced tornadoes. Two tornadoes were reported, one just southeast of Wynnewood and another north of Sulphur.||Additional severe thunderstorms developed across southern Oklahoma, but the main impacts had shifted from tornadoes to large hail and very heavy rainfall. By the time it was all said and done, five main supercells had occurred over parts of western and central Oklahoma, producing at least nine tornadoes. Widespread significant damage did not occur due to the location/short duration of the tornadoes, and only three minor injuries were reported.

The tornado developed 7 miles west-southwest of Wynnewood in Garvin county, and continued into Murray county, where the bulk of the damage occurred. Minor tree damage occurred on the Garvin county side of the tornado. Monetary damage estimates were not available.

This is a continuation of the Garvin county tornado that began 7 miles west-southwest of Wynnewood. Structural damage was concentrated in and around the community of Joy, along Joy Rd. east of Hwy 77. Several barns and outbuildings were heavily damaged, and some homes had roof damage. Extensive tree and power pole/line damage was also noted. Further to the east-northeast a home lost part of its roof. Monetary damage estimates were not available.

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 tornado watch, issued at 19:10 UTC and running to 02:35 UTC.

Issued (UTC)ExpiredProductOffice
19:10 UTC02:35 UTCTornado WatchOUN
23:49 UTC00:45 UTCSevere Thunderstorm WarningOUN
00:26 UTC01:15 UTCTornado WarningOUN
01:11 UTC02:15 UTCSevere Thunderstorm WarningOUN
01:33 UTC02:15 UTCTornado WarningOUN
02:10 UTC02:42 UTCTornado WarningOUN
02:35 UTC07:00 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 Slight Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. 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.

Norman, OK (KOUN), 00:00Z

1.5 hours before the tornado, 73 km from the path. May 20, 2010.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 00:00Z on 2010-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1598 joules per kilogram, CIN -6, lifted condensation level 954 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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 00:00Z on 2010-05-20The 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 259 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
1598 J/kg
Mixed-layer CIN
-6 J/kg
Surface CAPE
2220 J/kg
Mixed-layer LCL
954 m above ground
0-6 km bulk shear
28 kt
0-1 km bulk shear
30 kt
0-1 km storm-relative helicity
259 m²/s²
0-3 km storm-relative helicity
410 m²/s²
Significant tornado parameter
2.8
Supercell composite
18.7
0-3 km lapse rate
6.5 K/km

Open this sounding in Storm Lab

Norman, OK (KOUN), 12:00Z

10.5 hours after it, 73 km from the path. May 20, 2010.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2010-05-20Temperature 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 -374, lifted condensation level 1010 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 2010-05-20The 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 -63 square meters per square second, 0 to 6 km bulk shear 19 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
53 J/kg
Mixed-layer CIN
-374 J/kg
Surface CAPE
253 J/kg
Mixed-layer LCL
1010 m above ground
0-6 km bulk shear
19 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
-63 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
5.1 K/km

Open this sounding in Storm Lab

The surface observations

Pauls Valley Municipal Airport (PVJ), 15 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
23:48 UTC80.669.8160° 12 kt1003
00:08 UTC80.668160° 14 kt181002.4
00:28 UTC80.668160° 9 kt161003.4
00:48 UTC80.669.8160° 9 kt1003.4VCTS
01:08 UTC78.869.8170° 6 kt1003.7VCTSRA
01:28 UTC7771.6230° 6 kt1004.7+VCTSRA
01:50 UTC71.666.2140° 10 kt171004.4-TSRA
02:08 UTC69.862.6240° 4 kt141006.1+TSRA
02:27 UTC69.862.60° 0 kt1004.4-VCTSRA
02:48 UTC69.864.4210° 5 kt1004.4
03:08 UTC69.864.4180° 4 kt1004.4
03:30 UTC69.864.4170° 4 kt1004.7

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

The radar

The Norman radar (KTLX), 83 km away, was scanning. The volume nearest the touchdown began at 01:29 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
00:28 UTCHAIL 1SlaughtervilleCleveland, OK
00:45 UTCHAIL 2.5SlaughtervilleCleveland, OKTIME ESTIMATED BY RADAR.
00:50 UTCHAIL 1FosterGarvin, OK
01:00 UTCHAIL 1.75FosterGarvin, OK
01:10 UTCHAIL 11 W EtowahCleveland, OK
01:10 UTCHAIL 1.51 Sw Elmore CityGarvin, OK
01:31 UTCTORNADO6 Nne HennepinGarvin, OK
01:36 UTCHAIL 1.751 S MacombPottawatomie, OK
01:40 UTCHAIL 1.754 W St. LouisPottawatomie, OK
01:40 UTCTORNADO4 W WynnewoodGarvin, OKMULTIVORTEX ON THE GROUND 7 TO 10 MINUTES WITH POWER FLASHES AND SOME TREE DAMAGE OF UNKNOWN EXTENT.
01:52 UTCTORNADO4 Sse WynnewoodMurray, OKDAMAGE TO BUILDINGS AND TREES ON EAST SIDE OF JOY. TIME ESTIMATED BY RADAR.
02:16 UTCHAIL 1.757 Wnw RoffGarvin, OK
02:16 UTCTORNADO8 N SulphurMurray, OKBARN ROOF BLOWN OFF. RELAYED FROM ADA/PONTOTOC EOC. TIME ESTIMATED FROM RADAR.
02:32 UTCTSTM WND GST 702 W RoffPontotoc, OK
02:37 UTCHAIL 1.75RoffPontotoc, OK
03:15 UTCHAIL 1.759 Sw AdaPontotoc, OK
04:02 UTCHAIL 0.88TupeloCoal, OKRELAYED BY COAL COUNTY EM.

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

This ground now

The live radar over the trackEvery 2010 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

The other tornadoes of May 19, 2010

24 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 191:22 AM CDTEF0Ellis, OK0.550
May 191:56 AM CDTEF1Hutchinson, TX0.4100$28,000
May 193:15 AM CDTEF1Ellis, OK0.530
May 193:32 AM CDTEF0Ochiltree, TX1.150
May 193:24 PM CDTEF0Dewey, OK5.940
May 194:41 PM CDTEF0Kingfisher, OK0.150
May 195:08 PM CDTEF0Kingfisher, OK0.110
May 195:24 PM CDTEF0Logan, OK1.620
May 195:33 PM CDTEF1Kingfisher, OK14.0751
May 195:48 PM CDTEF0Gray, KS0.130
May 195:48 PM CDTEF0Gray, KS0.230
May 195:55 PM CDTEF0Finney, KS0.450
May 195:56 PM CDTEF0Gray, KS0.550
May 196:03 PM CDTEF1Payne, OK10.6200
May 196:04 PM CDTEF0Logan, OK0.110
May 196:26 PM CDTEF0Gray, KS0.330
May 196:57 PM CDTEF0Gray, KS0.230
May 197:03 PM CDTEF0Gray, KS0.450
May 197:09 PM CDTEF0Creek, OK0.150
May 197:37 PM CDTEF1Creek, OK5.0600$15,000
May 198:12 PM CDTEF1Lincoln, OK1.425
May 196:15 PM PDTEF0Grant, WA0.2100$2,000
May 198:46 PM CDTEF1Okfuskee, OK8.0500
May 199:05 PM CDTEF1Okfuskee, OK10.0500$15,000

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.