EF2 tornado, Sterling City, Texas, May 17, 2021

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 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mphthis tornado

   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

EF2

Date

May 17, 2021

Touchdown

7:11 PM CDT (00:11 UTC)

Lifted

7:47 PM CDT (00:47 UTC)

On the ground

36 minutes

Path length

11.4 miles (18.3 km)

Path width

1,056 yards (966 m)

Deaths

0

Injuries

0

County

Sterling County

Touchdown point

32.050, -101.180

Lift-off point

32.050, -101.180

Record number

2105171811-01

37 damage points were recorded along this path by NWS SJT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 115 mph.

• A nearby telephone pole was snapped. Storm chasers also provided video of this nearly quarter mile wide tornado.
• Multiple storm chasers also videotaped a tornado producing multiple vortices at this time.
• Storm chasers videotaped a tornado producing multiple vortices at this location.
• Another Storm Chaser videotaped this tornado at this time. Location estimated using radar. It had smaller multiple vortices.

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

Isolated dryline thunderstorms developed on the evening of May 16, well in advance of an approaching upper level low. These storms produced an EF-0 tornado on the north side of Anson, and large hail and damaging winds in Fisher and Haskell Counties. An approaching upper low from New Mexico interacted with a warm front on May 17, and produced a long track EF2 tornado across northern Sterling County along with several severe weather reports. Many storm chasers videotaped this tornado as it tracked across the wind farms. Heavy rain resulted in some flash flooding in Fisher County on the night of May 18 and in Irion County on the afternoon of May 19.

A NWS Storm Survey was conducted for this tornado that was videotaped by many storm chasers throughout it's track across northern Sterling County. We found many snapped Mesquite tree trunks and plenty of tree limb damage. The tornado moved large wind turbine propellers at two different locations, and it snapped 16 power poles across two ranches. The tornado caused a wind mill stand to bend over. A nearby crane located about a mile south of the tornado track or in the rear flank downdraft, measured a wind speed of 109 mph. The twister destroyed a camper. ||The collective videotapes on social media from the many storm chasers, showed the tornado starting out as a multi-vortex tornado in the northwest part of Sterling County around 711 PM CDT, transitioning to a large cone near the wind farms, and then becoming rain wrapped as it struck the gas plant at around 747 PM CDT. As the tornado struck a gas plant on State Highway 163, it slung a large dumpster about 300 yards into a nearby pasture, snapped a telephone pole and threw a large Conix container about 50 feet. It also bent one of the towers on the plant. ||Many thanks to the Sterling County Sheriff's Department, the Stewart Ranch, National Weather Service Midland, other ranchers and all of the storm chasers for their excellent assistance.

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

5 minutes of warning. NWS SJT issued a tornado warning for this county at 00:06 UTC, 5 minutes before the tornado touched down, in force until 00:45 UTC.

The county was under a tornado watch, issued at 20:04 UTC and running to 04:00 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 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:55 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.

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 2021 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

16 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.