EF3 tornado, Westville to Elm Spgs, Oklahoma, December 31, 2010

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.

Rating

EF3

Date

December 31, 2010

Touchdown

6:05 AM CST (12:05 UTC)

Lifted

6:27 AM CST (12:27 UTC)

On the ground

22 minutes

Path length

21.1 miles (33.9 km)

Path width

500 yards (457 m)

Deaths

4

Injuries

10

Property damage

$1.9 million

Counties

Adair, Washington and Benton counties

Touchdown point

35.998, -94.566

Lift-off point

36.198, -94.282

Record number

1012310605-01

34 damage points were recorded along this path by NWS TSA, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF3. The highest wind the damage implies is 142 mph.

• 13 large wood utility poles snapped in a line here and to the west of here
• 4 automobiles rolled 20 to 50 yards
• roof damage, broken windows; appears home was on the northern periphery of the tornado
• Lot that the mobile home where two people died originally resided; some of the tie downs are evident in the foreground

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

Unseasonably warm and moist air spread into eastern Oklahoma ahead of a cold front. Scattered thunderstorms developed in the late evening and early morning hours ahead of the cold front as a weak upper level disturbance passed through the region. Large hail and damaging wind gusts occurred with some of these storms. Another round of storms developed on the cold front as it moved into eastern Oklahoma a few hours before sunrise. Weak to moderate instability combined with very strong low level wind shear created an environment that supported supercell thunderstorm structures. Several supercells developed resulting in large hail and damaging wind gusts in the hours just before and after sunrise on the 31st. One of these supercells produced a long-track, strong tornado that began in Adair County, Oklahoma, and moved into Washington County, Arkansas, where it killed four people in and near the town of Cincinnati.

Unseasonably warm and moist air spread into northwestern Arkansas ahead of a cold front. Scattered thunderstorms developed in the late evening and early morning hours ahead of the cold front as a weak upper level disturbance passed through the region. Large hail and damaging wind gusts occurred with some of those storms. Another round of storms developed on the cold front over eastern Oklahoma as it pushed into the area. Weak to moderate instability combined with very strong low level wind shear created an environment that supported supercell thunderstorm structures. Several supercells developed resulting in large hail and damaging wind gusts in the hours just before and after sunrise on the 31st. One of these supercells produced a long-track, strong tornado that killed four people in and near the town of Cincinnati in Washington County. Debris was transported by the tornado into northern Benton County and was reported in Bella Vista and Pea Ridge. The Northwest Arkansas Regional Airport (XNA) was closed for three hours to remove the debris from the flight line. Another supercell produced a short-lived, weak tornado in Carroll County that moved into Missouri.

This segment is the first of six segments of this long-track tornado. A tornado developed just northeast of Westville and moved rapidly northeastward damaging a home, tossing or rolling four vehicles, snapping at least 13 large power poles, and snapping or uprooting large trees. Estimated maximum wind based on this damage was 125 mph. This tornado continued into Washington County, Arkansas.

This segment is the second of six segments of this long-track tornado. The tornado moved into Washington County snapping numerous trees as it approached the town of Cincinnati. In Cincinnati, the tornado destroyed several permanent homes, destroyed the volunteer fire station, destroyed a mobile home, damaged several other permanent homes, snapped or uprooted numerous trees, snapped numerous power poles, and destroyed barns and outbuildings. Two people were killed in the mobile home that was destroyed and a third person was killed either in or near a barn while he was tending to his cattle. At least seven injuries also occurred. The tornado was about 300 yards wide when it went through town. The maximum estimated wind speed in the tornado based on this damage was 140 mph.||The tornado continued to move rapidly northeastward and widened to about 500 yards northeast of Cincinnati. Several permanent homes were severely damaged, several mobile homes were destroyed, at least four chicken houses were destroyed, outbuildings were destroyed, numerous trees were snapped or uprooted, and power poles were snapped. A woman in one of the mobile homes that was destroyed was transported to a hospital with serious injuries. She later died from those injuries on January 4th.||The tornado continued into Benton County, Arkansas.

This segment is the third of six segments of this long-track tornado. The tornado severely damaged a couple permanent homes, destroyed a mobile home, destroyed barns, snapped or uprooted numerous trees, and snapped power poles in this portion of Benton County. Two injuries occurred in the mobile home that was destroyed on Winwood Ranch Road. The maximum estimated wind speed based on this damage was 130 mph.||The tornado continued into Washington County, Arkansas.

This segment is the fourth of six segments of this long-track tornado. Numerous trees were snapped or uprooted in this segment. Estimated maximum wind speed based on this damage was 125 mph.||The tornado moved northeastward and crossed back into Benton County, Arkansas.

This segment is the fifth of six segments of this long-track tornado. The tornado severely damaged a permanent home, destroyed a barn, snapped or uprooted numerous trees, and snapped power poles. The maximum estimated wind speed in this segment of the tornado based on this damage was 125 mph.||The tornado moved northeast and back into Washington County, Arkansas.

This segment is the sixth of six segments of this long-track tornado. The tornado overturned a box truck on Highway 412, injuring its driver, severely damaged a couple permanent homes, severely damaged a mobile home, snapped or uprooted numerous trees, and snapped numerous power poles. The maximum estimated wind speed in this segment of the tornado based on this damage was 125 mph.

The deaths

4 direct deaths are recorded for this tornado, each with what Storm Data knows of it.

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

5 minutes of warning. NWS TSA issued a tornado warning for this county at 12:00 UTC, 5 minutes before the tornado touched down, in force until 12:15 UTC.

The county was under a tornado watch, issued at 08:51 UTC and running to 14:00 UTC.

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 Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 05:44 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 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.

Siloam Spring(Awos) (SLG), 12 km from the path, in the two hours either side.

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

The Western Arkansas radar (KSRX), 90 km away, was scanning. The volume nearest the touchdown began at 12:05 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.

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

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

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

28 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.