EF1 tornado, May, Texas, May 18, 2017

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

May 18, 2017

Touchdown

8:38 PM CDT (01:38 UTC)

Lifted

9:00 PM CDT (02:00 UTC)

On the ground

22 minutes

Path length

4.4 miles (7.0 km)

Path width

880 yards (805 m)

Deaths

0

Injuries

0

County

Brown County

Touchdown point

31.942, -98.859

Lift-off point

31.951, -98.893

Record number

1705181938-01

28 damage points were recorded along this path by NWS SJT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 107 mph.

• This was tossed about 450 yards.
• 1 mile n lots of trees snapped
• A guy told us many trees were uprooted in the oil field located behind this house. There were many snapped trunks for up to a mile long . The tornado also wrapped the steel stair case around the oil tanks.

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

On May 18, a dryline clashed with a very unstable atmosphere to produce a long lived supercell, spawning several tornadoes, large hail and damaging thunderstorm wind reports. On May 19, a southward moving front triggered numerous severe storms as it clashed with a very unstable airmass, resulting in reports of large hail, damaging winds and tornadoes. A few of these tornadoes damaged some homes in northern Brown County on May 18.

A trained amateur radio spotter reported a tornado just northwest of May.

A National Weather Storm Survey team found evidence of an EF1 tornado with wind speeds of about 107 mph, which began about 3 miles southeast of May, Texas in Hogg Mountain. It moved southeast, then northeast and then turned back to the northwest and west. Because it was nearly stationary, the tornado appeared to rotate with the parent mesocyclone. The tornado uprooted many trees, snapped many tree trunks and branches of large Oak trees. The tornado tore off a roof of a mobile home, destroyed a chicken coop, damaged outdoor furniture, ripped off sheet metal from a barn and tossed it for over 100 yards. As the tornado continued to move west across County Road 478, it became about a half mile wide as it uprooted large Oak trees and snapped some tree trunks. Eyewitness accounts and a photograph indicated this tornado had multiple vortices.

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

23 minutes of warning. NWS SJT issued a tornado warning for this county at 01:15 UTC, 23 minutes before the tornado touched down, in force until 02:00 UTC.

The county was under a tornado watch, issued at 18:55 UTC and running to 03:00 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:58 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.

Brownwood Municipal (BWD), 19 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Dyess AFB radar (KDYX), 75 km away, was scanning. The volume nearest the touchdown began at 01:38 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 2017 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

47 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.