EF1 tornado, Afton to Wyandotte, Oklahoma, May 16, 2015

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 16, 2015

Touchdown

12:38 AM CDT (05:38 UTC)

Lifted

12:50 AM CDT (05:50 UTC)

On the ground

12 minutes

Path length

11.5 miles (18.5 km)

Path width

650 yards (594 m)

Deaths

0

Injuries

1

Property damage

$125,000

County

Ottawa County

Touchdown point

36.681, -94.829

Lift-off point

36.787, -94.686

Record number

1505162338-01

90 damage points were recorded along this path by NWS SGF and 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.

• Roof section from large outbuilding torn off and limbs downed. single power pole snapped.
• Small outbuilding also destroyed.
• multiple uprooted and snapped
• Apparent beginning point of Seneca MO Tornado

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

A strong upper level disturbance translated from the Southern Rockies into the Southern Plains on the 16th. Very moist and unstable air was in place across the Southern Plains as this system approached. Severe thunderstorms developed over western Oklahoma and northwestern Texas during the afternoon and moved eastward into eastern Oklahoma in the late evening. By the time the storms reached eastern Oklahoma, a well-organized squall line had evolved but due to very strong low level wind shear, multiple tornadoes occurred across the area along with widespread damaging wind. Locally heavy rainfall resulted in flash flooding in some areas through the early morning hours of the 17th.

This is the second segment of a two segment tornado. In Ottawa County, this tornado uprooted trees. Based on this damage, maximum estimated wind in this segment of the tornado was 90 to 100 mph.

This tornado developed just south of the E 230 Road and moved north-northeast destroying a mobile home, destroying several outbuildings, and snapping or uprooting trees. As the tornado approached the E 190 Road near the S 600 Road, it turned more to the northeast. Numerous trees were snapped or uprooted, a home was damaged, and outbuildings were damaged between the E 190 Road and Grand Lake. After moving over Grand Lake, the tornado damaged chicken houses and snapped or uprooted trees before dissipating east of Highway 10 near the E 160 Road. Based on this damage, maximum estimated wind in the tornado was 95 to 105 mph.

This is the first segment of a two segment tornado. In Ottawa County, this tornado snapped large tree limbs as it crossed the E 175 Road and uprooted trees near the state line, north of the S 700 Road. Based on this damage, maximum estimated wind in this segment of the tornado was 90 to 100 mph. This tornado continued into Newton County, MO.

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

22 minutes of warning. NWS TSA issued a tornado warning for this county at 05:16 UTC, 22 minutes before the tornado touched down, in force until 05:45 UTC.

The county was under a tornado watch, issued at 01:42 UTC and running to 07:05 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:22 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.

Grove Municipal Airport (GMJ), 14 km from the path, in the two hours either side.

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

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 2015 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

47 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.