Tornadoes · United States · Oklahoma · 2015

EF2 tornado, Valliant to Slim, Oklahoma, December 12, 2015

Name: EF2 tornado, Valliant to Slim, Oklahoma, December 12, 2015
Start: 2015-12-13T01:17:00.000Z
End: 2015-12-13T01:37:00.000Z
Location: Valliant to Slim, Oklahoma

From Valliant to Slim, this EF2 tornado ran 7.3 miles across McCurtain County on December 12, 2015, touching down at 7:17 PM CST and reaching 600 yards wide. It killed nobody and injured 3, and did $2.0 million of property damage.

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.

EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
EF2111 to 135 mphthis tornado
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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: EF2
Date: December 12, 2015
Touchdown: 7:17 PM CST (01:17 UTC)
Lifted: 7:37 PM CST (01:37 UTC)
On the ground: 20 minutes
Path length: 7.3 miles (11.8 km)
Path width: 600 yards (549 m)
Deaths: 0
Injuries: 3
Property damage: $2.0 million
County: McCurtain County
Touchdown point: 34.007, -95.138
Lift-off point: 34.104, -95.087
Record number: 1512121917-01

The damage survey

36 damage points were recorded along this path by NWS SHV and NWS TSA, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 120 mph.

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 strong upper level trough moved into the Central and Southern Plains during the morning and afternoon hours of December 12th. This trough ejected into the plains with a slight negative tilt which was indicative of strong jet dynamics in association with this trough. Likewise, low level and deep level shear was quite strong with this trough across Southeast Oklahoma during the late afternoon and evening hours of the 12th as well as the morning hours of the 13th. While instability was very weak, the strong shear made up for the development of strong to severe thunderstorms, some of which produced tornadoes across Southeast Oklahoma. Training of storm echoes also occurred which resulted in widespread flash flooding across the region as well.

An NWS Storm Survey team determined that the damage west of Valliant, Oklahoma was consistent with that of tornado damage. The tornado first touched down near U.S. Hwy. 70 and traveled in a northeast direction before lifting near Tommy Taylor Road or just south of Pine Creek Reservoir. Numerous trees were uprooted and/or snapped along the damage path. Sixteen homes suffered significant damage and 4 mobile homes were completely destroyed. Two persons were injured when their mobile home was destroyed. Another person was injured when their mobile home was rolled by the tornado.

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

What forecasters said that day

The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Shreveport, LA wrote its last area forecast discussion before the tornado touched down at Dec 12, 5:26 PM CST, 1 hour 51 minutes earlier.

Area forecast discussion, Dec 12, 5:26 PM CST, 1 hour 51 minutes before

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Hazardous weather outlook, Dec 12, 12:21 PM CST, 6 hours 56 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1221 PM CST SAT DEC 12 2015

ARZ050-051-059-060-070-071-LAZ001-002-010-OKZ077-TXZ096-097-
108>112-124>126-136>138-149>153-165-166-131200-
SEVIER-HOWARD-LITTLE RIVER-HEMPSTEAD-MILLER-LAFAYETTE-CADDO-
BOSSIER-DE SOTO-MCCURTAIN-RED RIVER-BOWIE-FRANKLIN-TITUS-CAMP-
MORRIS-CASS-WOOD-UPSHUR-MARION-SMITH-GREGG-HARRISON-CHEROKEE-RUSK-
PANOLA-NACOGDOCHES-SHELBY-ANGELINA-SAN AUGUSTINE-
1221 PM CST SAT DEC 12 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
ARKANSAS...NORTHWEST LOUISIANA...SOUTHEAST OKLAHOMA...EAST TEXAS
AND NORTHEAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

SHOWERS AND THUNDERSTORMS WILL INCREASE ACROSS EAST TEXAS AND
SOUTHEAST OKLAHOMA THIS AFTERNOON...AHEAD OF A STRONG UPPER LEVEL
STORM SYSTEM THAT WILL MOVE THROUGH THE DESERT SOUTHWEST AND INTO
THE SOUTHERN ROCKIES. AN ISOLATED SEVERE THUNDERSTORM THREAT WILL
EXIST LATE THIS AFTERNOON THROUGH TONIGHT ACROSS EAST TEXAS AND
EXTREME SOUTHEAST OKLAHOMA GIVEN THE VERY STRONG SHEAR IN
PLACE...BUT INSTABILITY WILL BE QUITE LIMITED AS SURFACE HEATING
WILL BE TAPERED BY THE DENSE CLOUD COVER AND RAIN. SHOULD A SEVERE
THREAT MATERIALIZE...DAMAGING WINDS AND ISOLATED TORNADOES WILL BE
THE PRIMARY THREATS. HOWEVER...LOCALLY HEAVY RAINFALL AND THE
THREAT FOR FLASH FLOODING WILL INCREASE ACROSS EAST TEXAS AND
SOUTHEAST OKLAHOMA TONIGHT AND SUNDAY MORNING...BEFORE A COLD
FRONT PUSHES THROUGH THE REGION.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD SUNDAY
MORNING...ALONG AND JUST AHEAD OF A COLD FRONT THAT WILL PUSH
THROUGH THE REGION. LOCALLY HEAVY RAINFALL AND THE THREAT FOR
FLASH FLOODING WILL CONTINUE SUNDAY MORNING BEFORE THE RAIN
DIMINISHES FROM WEST TO EAST BY MIDDAY. CUMULATIVE RAINFALL
AMOUNTS OF TWO TO FOUR INCHES...WITH ISOLATED HIGHER AMOUNTS IN
EXCESS OF SIX INCHES...WILL BE POSSIBLE BEFORE THE RAIN ENDS BY
EARLY AFTERNOON SUNDAY. IN ADDITION...AN ISOLATED SEVERE
THUNDERSTORM THREAT WILL CONTINUE SUNDAY MORNING WITH DAMAGING
WINDS AND ISOLATED TORNADOES POSSIBLE. COOLER AND DRIER AIR WILL
QUICKLY PUSH EAST IN WAKE OF THE COLD FRONTAL PASSAGE SUNDAY.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF EMERGENCY MANAGERS...SKYWARN NETWORKS...AND AMATEUR
RADIO OPERATORS...MAY BE NEEDED TONIGHT OVER EAST TEXAS AND
SOUTHEAST OKLAHOMA.

ARZ061-072-073-LAZ003>006-011>014-017>022-TXZ167-131200-
NEVADA-COLUMBIA-UNION-WEBSTER-CLAIBORNE-LINCOLN-RED RIVER-
BIENVILLE-JACKSON-OUACHITA-SABINE-NATCHITOCHES-WINN-GRANT-
CALDWELL-LA SALLE-
1221 PM CST SAT DEC 12 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARKANSAS...SOUTHWEST ARKANSAS...NORTH CENTRAL LOUISIANA...
NORTHWEST LOUISIANA AND EAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

ISOLATED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON OVER PORTIONS OF NORTHCENTRAL LOUISIANA AND SOUTHWEST
ARKANSAS. HOWEVER...SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED
TO INCREASE LATE TONIGHT AND ESPECIALLY AFTER DAYBREAK SUNDAY OVER
THE REGION. HOWEVER...NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

SHOWERS AND THUNDERSTORMS WILL SPREAD EAST ACROSS SOUTHWEST ARKANSAS
AND NORTHCENTRAL LOUISIANA SUNDAY...ALONG AND AHEAD OF A COLD
FRONT. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE...WITH WIDESPREAD
RAINFALL AMOUNTS OF ONE TO THREE INCHES EXPECTED. AN ISOLATED
SEVERE THUNDERSTORM THREAT WILL BE POSSIBLE AS WELL...MAINLY
ACROSS NORTHCENTRAL LOUISIANA. SHOULD THIS DEVELOP...DAMAGING
WINDS AND AN ISOLATED TORNADO WILL BE THE PRIMARY THREATS. THESE
SHOWERS AND THUNDERSTORMS WILL DIMINISH FROM WEST TO EAST SUNDAY
AFTERNOON AND EVENING...WITH COOLER AND DRIER AIR SPILLING EAST
BEHIND THE COLD FRONTAL PASSAGE.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF EMERGENCY MANAGERS...SKYWARN NETWORKS...AND AMATEUR
RADIO OPERATORS...WILL NOT BE NEEDED THIS AFTERNOON OR TONIGHT.

15

In the hours before

Local storm report, Dec 12, 5:55 PM CST, 1 hour 22 minutes before

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Local storm report, Dec 12, 5:56 PM CST, 1 hour 21 minutes before

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Local storm report, Dec 12, 6:05 PM CST, 1 hour 12 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE SHREVEPORT LA
605 PM CST SAT DEC 12 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0446 PM     TSTM WND DMG     MOUNT VERNON            33.17N  95.22W
12/12/2015                   FRANKLIN           TX   LAW ENFORCEMENT

            DAMAGE TO DAIRY FARM NEAR 90 WEST....317...AND 3190

&&

CORRECTED REMARKS

EVENT NUMBER SHV1500753

21

Special weather statement, Dec 12, 6:05 PM CST, 1 hour 12 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
605 PM CST SAT DEC 12 2015

TXZ136-149-150-130100-
CHEROKEE TX-RUSK TX-SMITH TX-
605 PM CST SAT DEC 12 2015

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN RUSK...NORTHEASTERN
CHEROKEE AND SOUTHEASTERN SMITH COUNTIES UNTIL 700 PM CST...

AT 605 PM CST...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
RUSK...MOVING NORTH AT 45 MPH.

WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
JACKSONVILLE...HENDERSON...WHITEHOUSE...RUSK...OVERTON...TROUP...NEW
LONDON...ARP...TURNERTOWN...JOINERVILLE...PONTA...MIXON...NEW SALEM...NEW
SUMMERFIELD...NEW CHAPEL HILL...GALLATIN...REKLAW...OAK HILL AND CONCORD.

LAT...LON 3237 9520 3227 9469 3165 9510 3170 9529
TIME...MOT...LOC 0005Z 195DEG 37KT 3172 9514

09

Special weather statement, Dec 12, 6:39 PM CST, 38 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
639 PM CST SAT DEC 12 2015

TXZ096-108-130130-
RED RIVER TX-FRANKLIN TX-
639 PM CST SAT DEC 12 2015

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN RED RIVER AND NORTHERN
FRANKLIN COUNTIES UNTIL 730 PM CST...

AT 639 PM CST...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
HAGANSPORT...MOVING NORTH AT 35 MPH.

WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
CLARKSVILLE...HAGANSPORT...BOGATA...BAGWELL...DETROIT...NEGLEY...JOHNTOWN
AND CUTHAND.

LAT...LON 3354 9531 3382 9525 3370 9485 3339 9508
      3340 9509 3339 9513 3332 9513 3329 9515
      3335 9531
TIME...MOT...LOC 0039Z 201DEG 31KT 3340 9522

09

Local storm report, Dec 12, 6:40 PM CST, 37 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE SHREVEPORT LA
640 PM CST SAT DEC 12 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0446 PM     TSTM WND DMG     MOUNT VERNON            33.17N  95.22W
12/12/2015                   FRANKLIN           TX   LAW ENFORCEMENT

            DAMAGE TO DAIRY FARM NEAR COUNTY ROAD 900 ...3170...AND
            3190

&&

CORRECTED REMARKS

EVENT NUMBER SHV1500753

21

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.

Shreveport, LA (KBAD), 00:00Z

1.3 hours before the tornado, 216 km from the path. December 13, 2015.

Skew-T log-p

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.

Hodograph

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: 87 J/kg
Mixed-layer CIN: -47 J/kg
Surface CAPE: 172 J/kg
Mixed-layer LCL: 1025 m above ground
0-6 km bulk shear: 55 kt
0-1 km bulk shear: 33 kt
0-1 km storm-relative helicity: 285 m²/s²
0-3 km storm-relative helicity: 332 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1
0-3 km lapse rate: 6.2 K/km

Open this sounding in Storm Lab

The surface observations

Idabel (4O4), 28 km from the path, in the two hours either side.

Time (UTC)	Temp (°F)	Dew point (°F)	Wind	Gust (kt)	Pressure (mb)	Weather
00:00 UTC

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

The radar

The Western Arkansas radar (KSRX), 153 km away, was scanning. The volume nearest the touchdown began at 01:16 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.

This ground now

The live radar over the track Every 2015 tornado in Oklahoma Every tornado in Oklahoma since 1950 Warnings in force in Oklahoma now The forecast where you are

The other tornadoes of December 12, 2015

7 more were confirmed in the United States that day.

Date	Time	Rating	Where	Path (mi)	Width (yd)	Injuries	Damage
December 12	2:25 PM CST	EF2	Smith, TX	1.8	150
December 12	3:54 PM CST	EF2	Montgomery, TX	2.2	100
December 12	4:18 PM CST	EF0	Franklin, TX	5.3	775	2	$2.0 million
December 12	4:59 PM CST	EF1	Red River, TX	1.0	187		$35,000
December 12	5:14 PM CST	EF1	Red River, TX	0.1	50		$10,000
December 12	5:53 PM CST	EF0	Gray, TX	0.0	50
December 12	6:03 PM CST	EF1	Choctaw, OK	3.3	250

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.