EF1 tornado, Chouteau to Mazie, Oklahoma, August 19, 2018

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 19, 2018

Touchdown

3:45 PM CDT (20:45 UTC)

Lifted

3:58 PM CDT (20:58 UTC)

On the ground

13 minutes

Path length

5.2 miles (8.4 km)

Path width

200 yards (183 m)

Deaths

0

Injuries

0

Property damage

$30,000

County

Mayes County

Touchdown point

36.076, -95.440

Lift-off point

36.124, -95.368

Record number

1808191445-01

25 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 99 mph.

• The Oklahoma Mesonet station measured 85 mph wind gusts at 10m above the ground and 98 mph wind gusts at 2m above the ground

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

Thunderstorms developed over northeastern New Mexico, southeastern Colorado, and the northwestern Texas Panhandle during the evening hours of the 18th. These storms moved east overnight and affected northeastern Oklahoma during the morning hours of the 19th. Locally heavy rainfall and some flash flooding occurred as these storms moved through the area. Another round of thunderstorms developed during the afternoon hours of the 19th across northeastern Oklahoma as a cold front moved into the area. These storms produced two tornadoes.

This is the second segment of a two-segment tornado. In Mayes County, the tornado snapped large tree limbs, tossed horse trailers, damaged outbuildings, and damaged mobile homes as it moved northeast from the W600 Road to north of the W550 Road. Based on this damage, maximum estimated wind in this segment of the tornado was 75 to 85 mph.

This tornado apparently developed near the S425 Road, just north of the E650 Road where large tree limbs were snapped. The tornado moved northeast and damaged a barn on the W640 Road, and damaged or destroyed outbuildings on the W630 Road. Large tree limbs were snapped as the tornado continued to move northeast, apparently dissipating north of the W620 Road and east of the S429 Road. Based on this damage, maximum estimated wind in the tornado was 90 to 100 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.

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 19:53 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.

Claremore Regional Airport (GCM), 22 km from the path, in the two hours either side.

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

The Tulsa radar (KINX), 17 km away, was scanning. The volume nearest the touchdown began at 20:47 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 2018 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

9 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.