EF1 tornado, Tulsa to Broken Arrow, Oklahoma, August 6, 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

August 6, 2017

Touchdown

1:27 AM CDT (06:27 UTC)

Lifted

1:31 AM CDT (06:31 UTC)

On the ground

4 minutes

Path length

2.9 miles (4.7 km)

Path width

400 yards (366 m)

Deaths

0

Injuries

0

Property damage

$220,000

Counties

Tulsa and Wagoner counties

Touchdown point

36.092, -95.794

Lift-off point

36.079, -95.745

Record number

1708060027-01

69 damage points were recorded along this path by NWS TSA, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 130 mph.

• vehicle in parking lot rolled over
• Roof of Chipolte blown off to the south

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

A surface low pressure system was positioned over southwestern Kansas during the evening of the 5th, with a stationary frontal boundary extending southeast from the low into northeastern Oklahoma and northwestern Arkansas. Thunderstorms developed over northwestern Oklahoma and south central Kansas during the evening hours and moved east into northeastern Oklahoma during the late evening hours of the 5th and early morning hours of the 6th. The thunderstorms evolved into a nearly solid line by the time they reached northeastern Oklahoma and resulted in widespread damaging wind. Very strong low-level wind shear ahead of the line allowed for the development of several areas of rotation along and within the leading edge of the thunderstorms. Several tornadoes formed from these low-level circulations, including a strong tornado that resulted in severe damage across portions of the City of Tulsa.

This tornado developed over a neighborhood east of S Harvard Avenue and south of E 36th Street S, where large tree limbs were snapped and homes were damaged. The tornado moved east-southeast crossing S Yale Avenue where numerous trees and power poles were snapped. Numerous businesses were damaged or destroyed between S Yale Avenue and S Sheridan Road along and within a few blocks of E 41st Street S. Some of the worst damage in the path was in this area. Some of the businesses in the area had the roofs blown off the structure and some had exterior walls blown down. Several vehicles were rolled in this area, and reportedly 30 people were injured there. Numerous other businesses sustained mainly roof, wall, and window damage between S Sheridan Road and Highway 169. Many power poles and trees were also blown down in this area. The tornado turned more easterly near Highway 169 and moved roughly along E 51st Street S, dissipating just before reaching N Aspen Avenue (S 145th East Avenue). Based on this damage, maximum estimated wind in the tornado was 120 to 130 mph.

This is the first segment of a two segment tornado. The tornado developed over a neighborhood along and north of E 51st Street S and west of S 177th East Avenue, where numerous homes received damage to their roofs and trees were damaged. The tornado moved east-southeast uprooting trees and snapping large tree limbs between Lynn Lane and County Line Road. Based on this damage, maximum estimated wind in this segment of the tornado was 90 to 100 mph. The tornado continued into Wagoner County.

This is the second segment of a two segment tornado. The tornado moved from Tulsa County into Wagoner County where it blew the roof off of an outbuilding. It continued moving east-southeast snapping large tree limbs and uprooting some trees. Based on this damage, maximum estimated wind in this segment of the tornado was 90 to 100 mph.

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

2 minutes of warning. NWS TSA issued a tornado warning for this county at 06:25 UTC, 2 minutes before the tornado touched down, in force until 06:34 UTC.

The county was under a severe thunderstorm watch, issued at 00:16 UTC and running to 09:00 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 General Thunderstorms Risk. The outlook in force was issued at 05:52 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.

The Tulsa radar (KINX), 21 km away, was scanning. The volume nearest the touchdown began at 06:28 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 OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

3 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.