EF0 tornado, Smithville, Oklahoma, April 14, 2011

1. EF065 to 85 mphthis tornado

   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 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.

Rating

EF0

Date

April 14, 2011

Touchdown

10:33 PM CDT (03:33 UTC)

Lifted

10:36 PM CDT (03:36 UTC)

On the ground

3 minutes

Path length

1.7 miles (2.7 km)

Path width

75 yards (69 m)

Deaths

0

Injuries

0

Property damage

$500

County

McCurtain County

Touchdown point

34.455, -94.662

Lift-off point

34.462, -94.634

Record number

1104142133-01

A strong upper level trough of low pressure moved into the southern plains, producing strong lift across portions of the Middle Red River Valley of Southeast Oklahoma, Northeast Texas and Southwest Arkansas. A dryline pushed into Eastern Oklahoma and Northeast Texas during the late afternoon and evening hours of April 14th. The atmosphere was moderately unstable across the region and the environment was conducive for supercells to develop. A few of these storms developed, producing a few tornadoes across McCurtain County with large hail and damaging wind gusts noted across the remainder of the region.

The National Weather Service conducted a storm survey in McCurtain County Oklahoma and found evidence of an EF0 tornado near Smithville. The tornado first touched down along US 259 southwest of Smithville where several trees were snapped on powerlines in front of a home. Some minor roof damage occurred to the home. The tornado crossed US 259 and snapped a few trees along the bank of Mountain Fork River. Near the end of the track���a large tree was snapped off along hwy 4 east of Smithville and several large branches were broken from trees in the area. Maximum winds are estimated at 65-70 mph.

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

3 minutes of warning. NWS SHV issued a tornado warning for this county at 03:30 UTC, 3 minutes before the tornado touched down, in force until 04:01 UTC.

The county was under a tornado watch, issued at 02:10 UTC and running to 07:34 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 Moderate Risk, with a 0.15 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 00:59 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.

The Western Arkansas radar (KSRX), 96 km away, was scanning. The volume nearest the touchdown began at 03:31 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.

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 2011 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

47 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.