Tornadoes · United States · Oklahoma · 2012

EF1 tornado, Cooperton, Oklahoma, April 13, 2012

Name: EF1 tornado, Cooperton, Oklahoma, April 13, 2012
Start: 2012-04-14T00:28:00.000Z
End: 2012-04-14T00:33:00.000Z
Location: Cooperton, Oklahoma

This EF1 tornado ran 5.0 miles across Kiowa County on April 13, 2012, touching down at 7:28 PM CDT and reaching 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.

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 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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: EF1
Date: April 13, 2012
Touchdown: 7:28 PM CDT (00:28 UTC)
Lifted: 7:33 PM CDT (00:33 UTC)
On the ground: 5 minutes
Path length: 5.0 miles (8.0 km)
Path width: 500 yards (457 m)
Deaths: 0
Injuries: 0
County: Kiowa County
Touchdown point: 34.849, -98.895
Lift-off point: 34.870, -98.826
Record number: 1204131828-01

What the Weather Service recorded

A severe weather event began during the early afternoon hours of Friday, April 13, 2012, and lasted through the early morning hours of Saturday, April 14, 2012. Around a dozen tornadoes, as well as large hail, and strong wind gusts were produced by the numerous thunderstorms that occurred during this event. Much of the severe weather occurred in parts of southwestern and central Oklahoma. However, thunderstorms did develop in other portions of Oklahoma as well during the event.||A moist airmass had been in place over much of the region for several days prior to April 13th, and several rounds of showers and thunderstorms had occurred during this period. On Friday, April 13th, a dryline and weak frontal boundary moved into the area extending from near southwestern and west central Oklahoma then northeast into north central Oklahoma by the early afternoon hours. The first storms developed in parts of southwestern Oklahoma and west Texas. However, it was several hours before the first tornado occurred. In fact, the potential for tornadoes increased during the early evening hours of April 13th as the low level jet (strong winds just above the surface) became stronger.||The first tornadic activity of the day occurred in central Oklahoma as a tornado touched down just southwest of Norman at 3:59 pm CDT, and then moved east-northeast through the heart of that city shortly after 4:00 pm CDT. This tornado was eventually rated an EF-1 as it damaged many businesses and homes, and numerous trees and power lines were also downed. No fatalities were reported with this rush hour tornado, but 20 injuries were reported. The same parent supercell thunderstorm that produced the Norman tornado also spawned a brief, weak tornado in Pottawatomie County 6 miles northwest of Shawnee, OK.||Meanwhile, supercell thunderstorms continued to develop in southwestern Oklahoma. Nine tornadoes occurred in this area with 3, and possibly 4 tornadoes occurring at one time with a storm near Cooperton, OK in Kiowa County during the evening of April 13th. Two tornadoes were also reported near Blair, OK in Jackson County, and 3 tornadoes were observed near Carnegie, OK in Caddo County.|Large hail and strong wind gusts was also reported with these severe thunderstorms. The largest hail reported was 3 inches in diameter and fell in an area 12 miles south of Sayre, OK. Several wind gusts to 70 mph were also reported.||Approximately 12 tornadoes occurred during this severe weather event. Fortunately, no fatalities or major injuries were reported with these tornadoes.

An off-duty NWS employee observed this tornado just southeast of Cooperton for a couple of minutes but is not known to have produced any damage. The specific location is estimated.

This tornado occurred simultaneously to the end of another tornado south of Cooperton. This tornado produced no known damage and the location is estimated.

Just after the dissipation of two other tornadoes near Cooperton, storm chasers reported a third tornado developed about 2 miles southwest of Cooperton. This large tornado initially moved southeast before crossing state highway 54, then turned northeast. Some damage occurred to a roof and a silo.

A large tornado developed east-northeast of Cooperton and moved north-northeast. Despite the large width, no damage was reported with this tornado and the specific location is estimated.

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 Norman, OK wrote its last area forecast discussion before the tornado touched down at Apr 13, 6:54 PM CDT, 34 minutes earlier.

Area forecast discussion, Apr 13, 6:54 PM CDT, 34 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
654 PM CDT FRI APR 13 2012

.DISCUSSION...
THE 00Z AVIATION DISCUSSION IS BELOW.

&&

.DISCUSSION...
HAVE LOW CONFIDENCE DURING THE NEXT 24 HOURS.

ISO TO SCT TSRA WILL CONTINUE MAINLY ALONG AND NORTH OF KAXS TO
KADH LINE BEFORE WEAKENING 05-09Z. KEPT VCTS AND TEMPO IN THESE
LOCATIONS INCLUDING KOKC AND KOUN. IF STORM DIRECTLY AFFECTS THESE
LOCATIONS...GUSTY WINDS...HAIL...AND LIFR CONDITIONS WOULD BE
POSSIBLE.

CONDITIONS WILL GENERALLY BE VFR OR MVFR THROUGH 05Z BEFORE MVFR
CONDITIONS OVERSPREAD THE ENTIRE AREA. KOKC...KOUN...AND KHBR
HAVE BEST SHOT FOR MVFR BEFORE 05Z. IFR CONDITIONS ARE POSSIBLE
NEARLY ANYWHERE 05-17Z...THOUGH BELIEVE MOST LOCATIONS WILL REMAIN
MVFR. VFR CONDITIONS WILL LIKELY DEVELOP OVER FAR WEST OKLAHOMA
AND WESTERN NORTH TEXAS 15-20Z.

SOUTH WINDS WILL BE GUSTY...ESPECIALLY AFTER 15Z.

MBS

&&

.PREV DISCUSSION... /ISSUED 244 PM CDT FRI APR 13 2012/

DISCUSSION...
BUSY EVENING EXPECTED AS CONVECTION IS BEGINNING ACROSS
SOUTHWEST OKLAHOMA. SEVERE STORMS ARE ANTICIPATED ACROSS
PORTIONS OF WESTERN AND CENTRAL OKLAHOMA THIS EVENING.
WIND FIELDS AND INSTABILITY ARE MORE SUFFICIENT FOR SEVERE
STORMS WITH VERY LARGE HAIL AND ISOLATED TORNADOES. THESE
WILL LIKELY LINGER THROUGH THE FIRST HALF OF THE NIGHT BEFORE
WANING.

ANOTHER SEVERE WEATHER EPISODE IS EXPECTED TO DEVELOP
DURING THE MID TO LATE AFTERNOON ON SATURDAY WITH ISOLATED
STORMS DEVELOPING ALONG THE DRYLINE ACROSS WESTERN OKLAHOMA
AND WORKING EAST AND NORTHEAST TOWARD CENTRAL OKLAHOMA. AGAIN
TORNADIC ACTIVITY WILL BE POSSIBLE WITH THESE STORMS. AS THE
MAIN UPPER WAVE MOVES OUT INTO THE PLAINS SATURDAY NIGHT...
EXPECT A LINE OF STORMS TO DEVELOP AND MOVE EAST ACROSS OKLAHOMA.
THESE STORMS WILL ALSO BE CAPABLE OF LARGE HAIL AND STRONG WINDS.

PRECIP ENDS ACROSS SOUTHEAST OKLAHOMA SUNDAY WITH MUCH OF NEXT OF
NEXT WEEK LOOKING DRY AND MILD.

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  65  79  57  75 /  50  20  60  30
HOBART OK         63  81  51  75 /  60  30  70  20
WICHITA FALLS TX  66  82  58  77 /  40  20  50  40
GAGE OK           62  79  45  70 /  40  30  30  10
PONCA CITY OK     65  77  58  73 /  60  20  70  30
DURANT OK         65  77  65  75 /  30  20  40  70

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&

23/17

Hazardous weather outlook, Apr 13, 7:15 PM CDT, 13 minutes before

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In the hours before

Local storm report, Apr 13, 5:43 PM CDT, 1 hour 45 minutes before

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Special weather statement, Apr 13, 5:56 PM CDT, 1 hour 32 minutes before

SPECIAL WEATHER STATEMENTNATIONAL WEATHER SERVICE NORMAN OK556 PM
CDT FRI APR 13 2012

OKZ007-012-132330-
GRANT OK-GARFIELD OK-
556 PM CDT FRI APR 13 2012

...SIGNIFICANT WEATHER ADVISORY FOR GRANT AND NORTH CENTRAL
GARFIELD COUNTIES UNTIL 630 PM CDT...

AT 555 PM CDT...STRONG THUNDERSTORMS EXTENDED FROM JUST NORTH OF
POND CREEK DOWN TO KREMLIN...MOVING NORTHEAST AT 45 MPH.

HAZARDS INCLUDE...
HAIL UP TO ONE-HALF INCH DIAMETER...
WIND GUSTS TO 40 MPH...

LOCATIONS IMPACTED INCLUDE...
MEDFORD...POND CREEK...KREMLIN...HUNTER...HILLSDALE...JEFFERSON
AND RENFROW.

LAT...LON 3652 9764 3649 9803 3694 9786 3700 9779
      3699 9762
TIME...MOT...LOC 2255Z 206DEG 38KT 3675 9777 3657 9791

Special weather statement, Apr 13, 6:13 PM CDT, 1 hour 15 minutes before

SPECIAL WEATHER STATEMENTNATIONAL WEATHER SERVICE NORMAN OK613 PM
CDT FRI APR 13 2012

OKZ017-018-024-132345-
BLAINE OK-KINGFISHER OK-CANADIAN OK-
613 PM CDT FRI APR 13 2012

...SIGNIFICANT WEATHER ADVISORY FOR BLAINE...KINGFISHER AND
NORTHWESTERN CANADIAN COUNTIES UNTIL 645 PM CDT...

AT 609 PM CDT...STRONG THUNDERSTORMS WERE LOCATED JUST
NORTHWEST OF EL RENO AND ALSO JUST NORTH OF HYDRO...MOVING NORTHEAST
AT 35 MPH.

HAZARDS INCLUDE...
HAIL UP TO THE SIZE OF NICKELS...
WIND GUSTS TO 40 MPH...

LOCATIONS IMPACTED INCLUDE...
KINGFISHER...GEARY...OKARCHE...GREENFIELD AND OMEGA.

LAT...LON 3592 9771 3561 9807 3561 9862 3590 9830
TIME...MOT...LOC 2309Z 228DEG 30KT 3563 9850 3563 9812

Special weather statement, Apr 13, 6:16 PM CDT, 1 hour 12 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
616 PM CDT FRI APR 13 2012

OKZ025-026-132345-
LINCOLN OK-OKLAHOMA OK-
616 PM CDT FRI APR 13 2012

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LINCOLN AND EAST
CENTRAL OKLAHOMA COUNTIES UNTIL 645 PM CDT...

AT 615 PM CDT...A STRONG THUNDERSTORM WAS LOCATED NEAR CHOCTAW...
MOVING NORTHEAST AT 20 MPH.

HAZARDS INCLUDE...
HAIL UP TO THE SIZE OF NICKELS...
WIND GUSTS TO 50 MPH...

LOCATIONS IMPACTED INCLUDE...
CHOCTAW...HARRAH AND JONES.

LAT...LON 3549 9703 3546 9711 3546 9714 3544 9715
      3541 9723 3556 9734 3569 9710
TIME...MOT...LOC 2315Z 239DEG 19KT 3552 9722

30

Special weather statement, Apr 13, 6:47 PM CDT, 41 minutes before

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Special weather statement, Apr 13, 7:10 PM CDT, 18 minutes before

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The surface observations

Hobart Municipal (HBR), 23 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 Altus AFB radar (KFDR), 56 km away, was scanning. The volume nearest the touchdown began at 00:26 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 2012 tornado in Oklahoma Every tornado in Oklahoma since 1950 Warnings in force in Oklahoma now The forecast where you are

The other tornadoes of April 13, 2012

13 more were confirmed in the United States that day.

Date	Time	Rating	Where	Path (mi)	Width (yd)
April 13	3:59 PM CDT	EF1	Cleveland, OK	6.0	600
April 13	5:24 PM CDT	EF0	Pottawatomie, OK	0.2	20
April 13	6:10 PM CDT	EF0	Jackson, OK	0.5	25
April 13	6:14 PM CDT	EF0	Jackson, OK	0.5	25
April 13	4:25 PM PDT	EF0	Elko, NV	0.9	50
April 13	6:30 PM CDT	EF0	Jackson, OK	2.0	400
April 13	7:25 PM CDT	EF0	Kiowa, OK	0.5	300
April 13	7:27 PM CDT	EF0	Kiowa, OK	0.2	100
April 13	7:52 PM CDT	EF0	Kiowa, OK	6.0	500
April 13	8:36 PM CDT	EF0	Caddo, OK	2.0	50
April 13	8:42 PM CDT	EF0	Caddo, OK	0.3	50
April 13	8:50 PM CDT	EF0	Caddo, OK	4.0	100
April 13	12:52 AM CDT	EF1	Canadian, OK	2.0	75

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.