EF0 tornado, Arcadia, Texas, June 21, 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

June 21, 2011

Touchdown

5:00 PM CDT (22:00 UTC)

Lifted

5:06 PM CDT (22:06 UTC)

On the ground

6 minutes

Path length

1.6 miles (2.5 km)

Path width

75 yards (69 m)

Deaths

0

Injuries

0

County

Shelby County

Touchdown point

31.783, -94.357

Lift-off point

31.764, -94.371

Record number

1106211600-01

Severe thunderstorms developed in the morning, and again in the|afternoon, on Tuesday, 21 June 2011. The thunderstorms formed after|several days of record setting hot weather, which was the result of a|persistent ridge of high pressure in the middle and upper atmosphere.|On 21 June 2011 a strong trough developed in the middle and upper levels|of the atmosphere moved from west to east across the central Plains|breaking down the upper level ridge over the Four State area. This|strong upper level trough allowed for gusty south winds to occur at the|surface of the atmosphere in the four State area, and brought enough|lift and instability to the atmosphere to allow scattered severe|thunderstorms to develop both in the morning and the afternoon of 21|June 2011. These thunderstorms produced wind damage and a few|tornadoes, in addition to brief episodes of heavy rainfall.

The National Weather Service conducted a storm survey in Shelby County and concluded that damage was the result of an EF0 tornado. Numerous trees were uprooted and snapped off and small branches were found across the damage path which started along CR 4060. The tornado moved south-southwest crossing FM 138 knocking over trees before lifting.

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

5 minutes of warning. NWS SHV issued a tornado warning for this county at 21:55 UTC, 5 minutes before the tornado touched down, in force until 22:30 UTC.

The county was under a severe thunderstorm watch, issued at 22:00 UTC and running to 02:56 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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:57 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 Shreveport radar (KSHV), 90 km away, was scanning. The volume nearest the touchdown began at 22:02 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 TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

9 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.