EF1 tornado, Lake Pat Cleburne to Alvarado, Texas, April 11, 2011

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 mphthis tornado

   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

EF1

Date

April 11, 2011

Touchdown

1:22 AM CDT (06:22 UTC)

Lifted

1:23 AM CDT (06:23 UTC)

On the ground

1 minutes

Path length

0.1 miles (0.2 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

2

Property damage

$100,000

County

Johnson County

Touchdown point

32.414, -97.233

Lift-off point

32.416, -97.231

Record number

1104110022-01

6 damage points were recorded along this path by NWS FWD, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 110 mph.

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

A strong upper level low pressure system over the southern Rockies aided in the late evening development of severe thunderstorms along a dryline across north central and central Texas. One of these storms was a strong linear mesoscale convective system which produced a swath of wind damage from Goldthwaite northeast into southern portions of the Dallas/Fort Worth Metroplex and continued northeast to near Sulphur Springs. A swath of wind damage consistent with 70 to 80 mph winds was associated with this storm. Other supercell thunderstorms in the area produced brief tornadoes and large hail.

A tornado began near County Road 1210 south of Pat Cleburne Lake and traveled approximately 1.5 miles to the east. The first signs of damage were to a garage and a house that was shifted off its foundation. Several trees were also blown down. Near the end of its track, the tornado damaged 5 homes with one of the homes sustaining heavy damage. This tornado has been rated an EF-1 with maximum estimated wind speeds of 100 to 110 mph.

There was a brief tornado touchdown in the city of Alvarado, just southwest of the intersection of Interstate 35W and Highway 67. A mobile home was overturned resulting in 2 minor injuries. The Equine Vet Building and 4 other commercial buildings sustained damage. This tornado has been rated an EF-1 with estimated maximum wind speeds of 90 mph.

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

7 minutes of warning. NWS FWD issued a tornado warning for this county at 06:15 UTC, 7 minutes before the tornado touched down, in force until 06:36 UTC.

The county was under a severe thunderstorm watch, issued at 00:02 UTC and running to 08:28 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 06:00 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 Dallas/Ft Worth radar (KFWS), 19 km away, was scanning. The volume nearest the touchdown began at 06:22 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

4 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.