Tornadoes · United States · Alabama · 2017
EF1 tornado, River Bend to Blocton Jct, Alabama, August 31, 2017
From River Bend to Blocton Jct, this EF1 tornado ran 0.6 miles across Bibb County on August 31, 2017, touching down at 7:28 PM CDT and reaching 200 yards wide. It killed nobody.
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.
EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- EF1
- Date
- August 31, 2017
- Touchdown
- 7:28 PM CDT (00:28 UTC)
- Lifted
- 7:30 PM CDT (00:30 UTC)
- On the ground
- 2 minutes
- Path length
- 0.6 miles (0.9 km)
- Path width
- 200 yards (183 m)
- Deaths
- 0
- Injuries
- 0
- County
- Bibb County
- Touchdown point
- 33.101, -87.172
- Lift-off point
- 33.107, -87.165
- Record number
- 1708311828-01
The damage survey
59 damage points were recorded along this path by NWS BMX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 95 mph.
- looking west. approx come from 220 deg
- looking east. healthy tree uprooted.
- roughly 300 degrees. trees snapped/uprooted
- roof detached tossed behind shed
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
What the Weather Service recorded
The remnants of Hurricane Harvey tracked northeast across Louisiana and along the Mississippi River. Feeder bands on the east side of Harvey produced four tornadoes across central Alabama.
NWS meteorologists surveyed damage in northern Bibb County and determined that the damage was consistent with an EF1 tornado. The tornado spun up along a hunting road south of Hopewell Church Road, where a couple of trees were downed. It paralleled Hopewell Church Road and reached its greatest intensity near a pond. Numerous trees were snapped and uprooted on both sides of the pond. The tornado dissipated north of the pond, prior to reaching Hopewell Church Road.
NWS meteorologists surveyed damage in northern Bibb County and determined that the damage was consistent with an EF0 tornado. The tornado developed just south of Old Woodstock Road along the northern side of the Colonial Pipeline with light tree damage observed. The tornado briefly intensified as it crossed Old Woodstock Road, uprooting several trees. Another batch of uprooted trees was seen toward the northeast, as the tornado moved through a stand of trees. The circulation then quickly weakened roughly 1.5 miles south of the Tuscaloosa County line.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
33 minutes of warning. NWS BMX issued a tornado warning for this county at 23:55 UTC, 33 minutes before the tornado touched down, in force until 01:00 UTC.
The county was under a tornado watch, issued at 16:15 UTC and running to 03:00 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 16:15 UTC | 03:00 UTC | Tornado Watch | BMX |
| 23:55 UTC | 01:00 UTC | Tornado Warning | BMX |
| 00:12 UTC | 00:33 UTC | Tornado Warning | BMX |
| 01:31 UTC | 03:30 UTC | Flood Advisory | BMX |
| 01:39 UTC | 23:00 UTC | Wind Advisory | BMX |
| 01:41 UTC | 02:30 UTC | Severe Thunderstorm Warning | BMX |
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 19:57 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.
Birmingham, AL (KBMX), 00:00Z
0.5 hours before the tornado, 37 km from the path. September 1, 2017.
- Mixed-layer CAPE
- 545 J/kg
- Mixed-layer CIN
- -7 J/kg
- Surface CAPE
- 1975 J/kg
- Mixed-layer LCL
- 1112 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 258 m²/s²
- 0-3 km storm-relative helicity
- 347 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 11.0
- 0-3 km lapse rate
- 6.9 K/km
Birmingham, AL (KBMX), 12:00Z
11.5 hours after it, 37 km from the path. September 1, 2017.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -70240 J/kg
- Surface CAPE
- 6 J/kg
- Mixed-layer LCL
- 797 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 89 m²/s²
- 0-3 km storm-relative helicity
- 116 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 4.8 K/km
The surface observations
Bessemer (EKY), 32 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 22:30 UTC | 150° 10 kt | 1009.5 | ||||
| 22:35 UTC | 160° 9 kt | 14 | 1009.5 | |||
| 22:39 UTC | 78.8 | 71.6 | 150° 10 kt | 15 | 1009.5 | TS |
| 22:40 UTC | 160° 10 kt | 16 | 1009.5 | |||
| 22:45 UTC | 160° 8 kt | 1009.5 | ||||
| 22:50 UTC | 160° 9 kt | 14 | 1009.5 | |||
| 22:54 UTC | 80.6 | 71.6 | 150° 10 kt | 16 | 1009.5 | |
| 22:55 UTC | 150° 10 kt | 1009.5 | ||||
| 22:56 UTC | 80 | 72 | 160° 10 kt | 16 | 1009.5 | |
| 23:00 UTC | 160° 10 kt | 1009.1 | ||||
| 23:05 UTC | 150° 9 kt | 1009.1 | ||||
| 23:10 UTC | 150° 9 kt | 15 | 1009.1 | |||
| 23:15 UTC | 150° 11 kt | 16 | 1009.1 | |||
| 23:20 UTC | 150° 9 kt | 1009.1 | ||||
| 23:25 UTC | 180° 8 kt | 1008.8 | ||||
| 23:30 UTC | 160° 9 kt | 1008.8 | ||||
| 23:35 UTC | 160° 10 kt | 15 | 1008.8 | |||
| 23:40 UTC | 150° 8 kt | 1008.5 | ||||
| 23:45 UTC | 160° 9 kt | 1008.5 | ||||
| 23:50 UTC | 150° 9 kt | 1008.5 | ||||
| 23:55 UTC | 150° 11 kt | 1008.1 | ||||
| 23:56 UTC | 80 | 72 | 150° 11 kt | 19 | 1008.1 | |
| 00:00 UTC | 150° 10 kt | 1008.1 | ||||
| 00:05 UTC | 150° 12 kt | 1008.1 | ||||
| 00:10 UTC | 150° 10 kt | 1008.1 | ||||
| 00:20 UTC | 150° 11 kt | 16 | 1007.8 | -RA | ||
| 00:25 UTC | 150° 10 kt | 1007.8 | -RA | |||
| 00:30 UTC | 150° 14 kt | 19 | 1007.8 | |||
| 00:35 UTC | 160° 12 kt | 18 | 1007.8 | -RA | ||
| 00:39 UTC | 78.8 | 71.6 | 160° 10 kt | 22 | 1007.8 | VCTS RA |
| 00:40 UTC | 150° 10 kt | 16 | 1007.8 | RA | ||
| 00:45 UTC | 150° 12 kt | 1007.8 | RA | |||
| 00:50 UTC | 150° 12 kt | 1007.5 | -RA | |||
| 00:55 UTC | 160° 10 kt | 1007.5 | -RA | |||
| 00:56 UTC | 78 | 72 | 160° 9 kt | 21 | 1007.5 | TSRA |
| 01:00 UTC | 150° 10 kt | 1007.5 | RA | |||
| 01:05 UTC | 150° 11 kt | 1007.1 | -RA | |||
| 01:10 UTC | 160° 11 kt | 1007.1 | -RA | |||
| 01:15 UTC | 130° 11 kt | 1007.1 | -RA | |||
| 01:20 UTC | 21 | 1007.8 | -RA | |||
| 01:25 UTC | 240° 14 kt | 1008.5 | -RA | |||
| 01:26 UTC | 75.2 | 73.4 | 230° 12 kt | 25 | 1008.5 | TSRA BR |
| 01:30 UTC | 220° 6 kt | 1007.8 | +RA BR | |||
| 01:35 UTC | 220° 9 kt | 16 | 1008.1 | -RA BR | ||
| 01:40 UTC | 240° 11 kt | 1008.5 | RA | |||
| 01:45 UTC | 170° 5 kt | 1008.1 | +RA | |||
| 01:50 UTC | 1009.1 | +RA BR | ||||
| 01:55 UTC | 210° 10 kt | 15 | 1009.1 | +RA BR | ||
| 01:56 UTC | 74 | 74 | 200° 10 kt | 23 | 1009.1 | TSRA BR |
| 02:00 UTC | 1009.1 | RA BR | ||||
| 02:05 UTC | 1009.1 | +RA BR | ||||
| 02:10 UTC | 1008.8 | +RA BR | ||||
| 02:12 UTC | 71.6 | 71.6 | 200° 16 kt | 27 | 1008.8 | TSRA |
| 02:15 UTC | 20 | 1009.1 | RA | |||
| 02:20 UTC | 190° 12 kt | 18 | 1009.1 | -RA | ||
| 02:25 UTC | 71.6 | 71.6 | 180° 9 kt | 19 | 1009.1 | VCTS -RA |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Birmingham radar (KBMX), 38 km away, was scanning. The volume nearest the touchdown began at 00:30 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) | Report | Where | County | Remark |
|---|---|---|---|---|
| 23:57 UTC | TORNADO | 1 Se Harmon | Bibb, AL | NWS METEOROLOGISTS SURVEYED DAMAGE IN SOUTHWEST BIBB COUNTY AND FOUND THAT THE DAMAGE WAS CONSISTENT WITH AN EF1 TORNADO, WITH MAXIMUM SUSTAINED WINDS NEAR 90. NO INJURIES OR FATALITIES. |
| 00:09 UTC | TSTM WND DMG | 2 Wsw Eoline | Bibb, AL | TREES AND POWER LINES DOWN ACROSS PORTIONS OF WARD SCHOOL ROAD, WEST EOLINE ROAD AND BEAR CREEK ROAD. POSSIBLE TORNADO. REPORT RELAYED BY SOCIAL MEDIA. LOCATION APPROXIMATE. |
| 00:11 UTC | TORNADO | 1 Se Harmon | Bibb, AL | STORM CHASER TOOK VIDEO OF TORNADO CROSSING U.S. HIGHWAY 82 IN BIBB COUNTY NEAR EOLINE. TIME APPROXIMATE. |
| 00:28 UTC | TORNADO | 3 Wsw West Blocton | Bibb, AL | NWS METEOROLOGISTS SURVEYED DAMAGE NEAR HOPEWELL CHURCH ROAD AND DETERMINED THAT IT WAS CAUSED BY AN EF1 TORNADO WITH 95 MPH WINDS. |
| 00:42 UTC | TORNADO | 1 E North Bibb | Bibb, AL | NWS METEOROLOGISTS SURVEYED DAMAGE NEAR OLD WOODSTOCK ROAD AND DETERMINED THAT IT WAS CAUSED BY AN EF0 TORNADO WITH 75 MPH WINDS. |
| 01:55 UTC | TSTM WND DMG | 1 Nw Alabaster | Shelby, AL | TREE DOWN AT HIGHWAY 95 AND BIG CLOUD CIRCLE. |
| 02:56 UTC | TSTM WND DMG | 1 S Shelby | Shelby, AL | TREE DOWN AT COUNTY 46 AND COUNTY 47. |
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 AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are
The other tornadoes of August 31, 2017
15 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| August 31 | 8:19 AM CDT | EF0 | Phillips, AR | 1.7 | 50 | $15,000 | ||
| August 31 | 11:57 AM CDT | EF0 | Benton, MS | 0.3 | 30 | $25,000 | ||
| August 31 | 1:13 PM CDT | EF0 | Lee, MS | 1.1 | 40 | |||
| August 31 | 1:23 PM CDT | EF1 | Itawamba, MS | 2.5 | 150 | $150,000 | ||
| August 31 | 1:43 PM CDT | EF0 | Prentiss, MS | 0.3 | 30 | $50,000 | ||
| August 31 | 3:07 PM CDT | EF0 | Hardin, TN | 1.3 | 50 | $10,000 | ||
| August 31 | 3:40 PM CDT | EF2 | Pickens, AL | 31.2 | 600 | 6 | ||
| August 31 | 4:19 PM CDT | EF0 | Perry, TN | 0.3 | 50 | $10,000 | ||
| August 31 | 4:37 PM CDT | EF0 | Hardin, TN | 0.8 | 70 | $10,000 | ||
| August 31 | 5:11 PM CDT | EF0 | Maury, TN | 3.4 | 75 | $10,000 | ||
| August 31 | 6:57 PM CDT | EF1 | Bibb, AL | 6.5 | 100 | |||
| August 31 | 7:42 PM CDT | EF0 | Bibb, AL | 0.3 | 35 | |||
| August 31 | 8:58 PM CDT | EF2 | Cullman, AL | 13.6 | 300 | |||
| August 31 | 11:21 PM CDT | EF1 | Davidson, TN | 0.6 | 75 | $25,000 | ||
| August 31 | 11:47 PM CDT | EF0 | Davidson, TN | 0.9 | 50 | $15,000 |
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.