Tornadoes · United States · Texas · 2017

EF0 tornado, Galveston, Texas, August 25, 2017

This EF0 tornado ran 0.1 miles across Galveston County on August 25, 2017, touching down at 2:18 PM CDT and reaching 20 yards wide. It killed nobody, and did $500 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

    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 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.

The record

Rating
EF0
Date
August 25, 2017
Touchdown
2:18 PM CDT (19:18 UTC)
Lifted
2:19 PM CDT (19:19 UTC)
On the ground
1 minutes
Path length
0.1 miles (0.2 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
Property damage
$500
County
Galveston County
Touchdown point
29.310, -94.770
Lift-off point
29.312, -94.770
Record number
1708251318-01

What the Weather Service recorded

Harvey made landfall as a category 4 hurricane near Rockport, Texas during the evening of August 25th. The storm then weakened to a tropical storm and slowed, looping back and tracking over SE Texas then back over the Gulf of Mexico making a second landfall along the Louisiana coast during the early morning hours of August 30th. Over that 5 day period over Southeast Texas TS Harvey produced catastrophic flooding with a large area of 30 to 60 inches of rain, 23 tornadoes, tropical storm force winds and a moderate storm surge near Matagorda Bay. In some of the heavier bands rain fell at a rate of over 5 inches per hour. This copious record amount of rain over a led to catastrophic flooding. Thousands of homes, businesses, and roads were flooded due to flash flooding and sheet flow from long duration intense rain. Main stem rivers and adjoining tributaries, creeks and bayous reached full capacity and came out of their banks and this also contributed to the massive flooding across southeastern Texas.

Funnel cloud sighting with fence damage near Ferry Road.

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

The warnings

4 minutes of warning. NWS HGX issued a tornado warning for this county at 19:14 UTC, 4 minutes before the tornado touched down, in force until 19:45 UTC.

The county was under a tornado watch, issued at 19:02 UTC and running to 06:49 UTC.

Issued (UTC)ExpiredProductOffice
09:00 UTC08:04 UTCFlash Flood WatchHGX
18:48 UTC19:15 UTCTornado WarningHGX
19:02 UTC06:49 UTCTornado WatchHGX
19:14 UTC19:45 UTCTornado WarningHGX
19:41 UTC20:00 UTCTornado WarningHGX
19:44 UTC19:55 UTCTornado WarningHGX
20:42 UTC21:15 UTCTornado WarningHGX
21:07 UTC21:30 UTCTornado WarningHGX
21:37 UTC23:30 UTCFlood AdvisoryHGX
23:39 UTC00:15 UTCTornado WarningHGX
23:53 UTC00:03 UTCTornado WarningHGX
00:42 UTC02:45 UTCFlood AdvisoryHGX
00:45 UTC01:15 UTCTornado WarningHGX
01:33 UTC02:00 UTCTornado WarningHGX
02:33 UTC03:00 UTCTornado WarningHGX
02:40 UTC03:00 UTCTornado WarningHGX
04:50 UTC05:15 UTCTornado WarningHGX

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 forecast that day

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 16:04 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 air that afternoon

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.

Lake Charles Mun, LA (KLCH), 12:00Z

7.3 hours before the tornado, 176 km from the path. August 25, 2017.

Skew-T log-pSkew-T log-p diagram, Lake Charles Mun, LA at 12:00Z on 2017-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1337 joules per kilogram, CIN -25, lifted condensation level 748 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Lake Charles Mun, LA at 12:00Z on 2017-08-25The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 102 square meters per square second, 0 to 6 km bulk shear 20 knots.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
1337 J/kg
Mixed-layer CIN
-25 J/kg
Surface CAPE
884 J/kg
Mixed-layer LCL
748 m above ground
0-6 km bulk shear
20 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
124 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.5 K/km

Open this sounding in Storm Lab

Lake Charles Mun, LA (KLCH), 00:00Z

4.7 hours after it, 176 km from the path. August 26, 2017.

Skew-T log-pSkew-T log-p diagram, Lake Charles Mun, LA at 00:00Z on 2017-08-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 275 joules per kilogram, CIN -69, lifted condensation level 739 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Lake Charles Mun, LA at 00:00Z on 2017-08-26The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 119 square meters per square second, 0 to 6 km bulk shear 31 knots.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
275 J/kg
Mixed-layer CIN
-69 J/kg
Surface CAPE
810 J/kg
Mixed-layer LCL
739 m above ground
0-6 km bulk shear
31 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
119 m²/s²
0-3 km storm-relative helicity
253 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.3
0-3 km lapse rate
4.5 K/km

Open this sounding in Storm Lab

The radar

The Houston radar (KHGX), 35 km away, was scanning. The volume nearest the touchdown began at 19:17 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
19:23 UTCTORNADO 09 Ne GalvestonGalveston, TXPUBLIC REPORTS A FUNNEL CLOUD AND A METAL FENCE DAMAGED NEAR FERRY RD IN GALVESTON
19:23 UTCTORNADO 09 Ne GalvestonGalveston, TXPUBLIC REPORTS A FUNNEL CLOUD AND A METAL FENCE DAMAGED NEAR FERRY RD IN GALVESTON.
19:23 UTCTORNADO9 Ne GalvestonGalveston, TXPUBLIC REPORTS A FUNNEL CLOUD AND A METAL FENCE DAMAGED NEAR FERRY RD IN GALVESTON
20:47 UTCTORNADO 09 Ne GalvestonGalveston, TXTORNADO DAMAGED MCDONALDS SIGN AT SEAWALL BLVD AND BROADWAY AVE. ALSO DAMAGE TO AWNINGS AT APARTMENT COMPLEX.
20:47 UTCTORNADO9 Ne GalvestonGalveston, TXTORNADO DAMAGED MCDONALDS SIGN AT SEAWALL BLVD AND BROADWAY AVE.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2017 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

The other tornadoes of August 25, 2017

8 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 253:30 PM CDTEF0Brazoria, TX0.230$30,000
August 254:08 PM CDTEF1Matagorda, TX2.250$500,000
August 254:14 PM CDTEF0Calhoun, TX0.220$10,000
August 256:11 PM CDTEF0Brazoria, TX4.050$100,000
August 2510:44 PM CDTEF0Brazoria, TX4.850$100,000
August 2512:28 AM CDTEF0Brazoria, TX4.350$50,000
August 2512:50 AM CDTEF1Brazoria, TX1.650$1.0 million
August 2512:56 AM CDTEF1Fort Bend, TX1.5100$500,000

What this means

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.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.