EF1 tornado, Lackland Afb to (Skf)Kelly Afb San A, Texas, October 9, 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

October 9, 2011

Touchdown

1:10 AM CDT (06:10 UTC)

Lifted

1:20 AM CDT (06:20 UTC)

On the ground

10 minutes

Path length

1.9 miles (3.0 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$1.0 million

County

Bexar County

Touchdown point

29.366, -98.632

Lift-off point

29.392, -98.642

Record number

1110090010-01

Southeasterly flow brought deep boundary layer moisture into South Central Texas during the day and evening of October 8. When an upper level trough of low pressure moved across the southern plains, the combination caused thunderstorms which produced heavy rain. One of these storms also produced a tornado in San Antonio.

A tornado touched down on the southwest side of San Antonio near the intersection of Loop 410 and Medina Base Road. The tornado moved toward the north-northwest and dissipated near the intersection of Allenhurst and Springvale Drives. The path of tornado was 1.9 miles long with a maximum width of 50 yards. The damage from the tornado was rated EF1 with maximum winds estimated at 90 to 100 mph. The tornado caused roof damage to a number of homes along its path including in the Ridgestone subdivision, along Parallel Drive, near the intersection of Cedarhurst and Gage Drives, and on north to its end. It also hit near the post office at 5510 SW Loop 410 where it destroyed 15 postal trucks and damaged 7 others. In addition, it damaged 2 office buildings on Valley Hi Drive and damaged the roof and a new building at the Sam Rayburn Middle School. In all, over 71 properties were impacted by the tornado with 3 homes receiving major damage. No injuries or deaths were reported.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

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, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 05:27 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 Austin/San Antonio radar (KEWX), 69 km away, was scanning. The volume nearest the touchdown began at 06:10 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

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.