EF1 tornado, Cotton Center, Texas, April 17, 2007

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 17, 2007

Touchdown

1:57 PM CDT (18:57 UTC)

Lifted

2:03 PM CDT (19:03 UTC)

On the ground

6 minutes

Path length

2.0 miles (3.2 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

Property damage

$35,000

County

Hale County

Touchdown point

33.980, -102.025

Lift-off point

33.957, -102.000

Record number

0704171257-01

A potent middle and upper atmospheric storm system moved eastward over the west Texas South Plains on the 17th. This system resulted in the development of numerous thunderstorms across the region. With abundant sunshine and heating that occurred early in the day beneath very cold mid-level temperatures aloft, steep vertical temperature lapse rates developed. With strong instability in place, thunderstorms developed rapidly around midday in the vicinity of a stalled frontal boundary that stretched from northwest to southeast across the region.|Thunderstorm updrafts were enhanced by the cold mid-level temperatures, and this made them efficient for stretching small circulations along the frontal boundary. This process, combined with complex storm interactions and multi-cell storm mergers, resulted in the development of at least six tornadoes across the South Plains region. All of the tornadoes were weak, but some damage did occur in Hale and Lubbock Counties, including within the city of Lubbock. The storms also produced large hail up to the size of ping pong balls.

A farmstead was damaged by an apparent tornado that moved southeastward across portions of western Hale County. The tornado uprooted two large trees and destroyed a center pivot irrigation system. No structural damage or injuries were reported. The damage and reports from local residents corresponds to a strong low-level circulation in Doppler radar velocities.

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. One was issued for the county at another hour that day.

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 16:30 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 Lubbock radar (KLBB), 39 km away, was scanning. The volume nearest the touchdown began at 18:57 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 2007 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

7 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.