EF1 tornado, La Porte Muni Arpt to Bay Oaks, Texas, March 29, 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

March 29, 2017

Touchdown

2:55 PM CDT (19:55 UTC)

Lifted

2:58 PM CDT (19:58 UTC)

On the ground

3 minutes

Path length

0.4 miles (0.7 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$27,000

County

Harris County

Touchdown point

29.649, -95.071

Lift-off point

29.643, -95.070

Record number

1703291355-01

17 damage points were recorded along this path by NWS HGX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 105 mph.

• Shipping containers blown off stacks and moved.
• roof peeled off toward the southeast
• empty storage tanks blown off stacks in varying directions. each weigh 4.25 tons.
• soil may be soft, no other damage surrounding tree

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

A line of thunderstorms moved across southeast Texas during the morning and afternoon hours and produced several tornadoes, hail, wind damage and some flooding.

This EF-1 tornado was the first of four tornadoes from a parent mesocyclone associated with a large HP supercell that tracked across southeast Harris County and into Chambers County. This small track tornado spun up quickly along the back side of the parent mesocyclone with a track from the north northwest to the south southeast, passing directly over a business and damaging metal industrial buildings from south of Fairmont Parkway to west of Bay Park Road. Cars were pushed and stacked into and on top of each other in the parking lot. A large semi-trailer was slid into several vehicles. There was significant roof damage to a large storage facility before the tornado ended in a small open track of land to the south. Estimated peak winds were 110 mph.

This EF-0 tornado is the second brief tornado from the larger mesocyclone associated with a fast moving HP supercell. It began along or just east of Highway 146 near or just south of Main Street and ended at Southern Morgan's Point near the Bay. There was considerable damage to trees and power lines across much of La Porte east of Highway 146. This location made tornado identification difficult as the area also was located within strong south southeasterly inflow winds followed by stronger westerly straight line winds as the first couplet gusted out and a secondary couplet evolved over the Barbours Cut Port Facility. It appears this tornado likely moved across the city roughly from west to east from the same velocity couplet which produced the first brief tornado in Pasadena as it rotated around the larger mesocyclone. Estimated peak winds were 70 to 80 mph.

This EF-1 was the third brief tornado with the larger mesocyclone associated with the HP supercell which moved across La Porte and Morgans Point. This couplet |was well defined on the Houston Hobby terminal doppler radar which spun up quickly|along the north side of strong westerly outflow winds from the initial couplet that was responsible for two earlier weak tornadoes near and in parts of La Porte. This tornado was witnessed to start near the railroad tracks near Highway 146 and it tracked east southeastward across the Barbours Cut Port Facility and parts of Morgans Point. Much of the more significant damage was to industrial areas around the Port complex. Large steel storage tanks were bent inward from the wind, and many large, metal shipping containers were toppled over. The tornado lifted near the eastern end of Morgans Point near the Ship Channel. Estimated peak winds were around 105 mph.

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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 16:47 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.

Houston/Ellington (EFD), 10 km from the path, in the two hours either side.

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

The Houston radar (KHGX), 19 km away, was scanning. The volume nearest the touchdown began at 19:57 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 2017 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

17 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.