EF1 tornado, Collinsville to Sageeyah, Oklahoma, May 11, 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 11, 2017

Touchdown

2:27 PM CDT (19:27 UTC)

Lifted

2:33 PM CDT (19:33 UTC)

On the ground

6 minutes

Path length

3.1 miles (5.0 km)

Path width

350 yards (320 m)

Deaths

0

Injuries

0

County

Rogers County

Touchdown point

36.377, -95.662

Lift-off point

36.420, -95.648

Record number

1705111327-01

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

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

A slow-moving upper level storm system moved from the Southern Rockies into the Southern Plains during the 10th and 11th. Warm, moist, and unstable air was in place across eastern Oklahoma ahead of this system. Several disturbances translated across the Southern Plains ahead of the main system, resulting in multiple rounds of strong to severe thunderstorm development along the associated frontal boundary that slowly progressed eastward and southward through the region. These storms produced several tornadoes, hail up to golfball size, damaging wind, and locally heavy rainfall.

A supercell thunderstorm rapidly developed near Owasso. A tornado developed as the storm approached N 161st E Avenue to the south of 106th Street N where tree limbs were snapped and barns were damaged. The tornado moved northeast damaging the roofs of about 70 homes, destroying outbuildings, uprooting trees, rolling camper trailers, and blowing down power poles between 106th Street N and 109th Street N. The tornado turned more east at about N 173rd E Avenue and then dissipated to the east of N 177th E Avenue. Based on this damage, maximum estimated wind in the tornado was 90 to 100 mph.

The Owasso tornado dissipated and the supercell thunderstorm that produced it cycled another tornado southeast of Oologah. The first damage from this tornado was on Northaven Road, north of the E 445 Road, where trees were damaged. From there, the tornado moved north-northeast uprooting and snapping trees. It crossed Highway 88 west of the N 4133 Road, where large tree limbs were snapped, and then dissipated north of Highway 88 where trees were uprooted just south of Lake Oologah. Based on this damage, maximum estimated wind in the tornado was 100 to 110 mph.

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

25 minutes of warning. NWS TSA issued a tornado warning for this county at 19:02 UTC, 25 minutes before the tornado touched down, in force until 19:30 UTC.

The county was under a severe thunderstorm watch, issued at 18:00 UTC and running to 02:00 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 Enhanced Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 16:37 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), 26 km away, was scanning. The volume nearest the touchdown began at 19:24 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

10 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.