EF1 tornado, Marlow to Bray, Oklahoma, May 20, 2013

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 20, 2013

Touchdown

3:07 PM CDT (20:07 UTC)

Lifted

3:22 PM CDT (20:22 UTC)

On the ground

15 minutes

Path length

4.0 miles (6.4 km)

Path width

200 yards (183 m)

Deaths

0

Injuries

0

Property damage

$20,000

County

Stephens County

Touchdown point

34.596, -97.933

Lift-off point

34.640, -97.890

Record number

1305201407-01

A tornado outbreak occurred during the afternoon and evening hours of the 20th. Several tornadoes occurred from central Oklahoma down through south central Oklahoma near the Red River. The strongest tornado touched down near Newcastle and traveled through Moore and south Oklahoma City. This tornado caused catastrophic damage in these areas, with a maximum rating of EF-5. The tornado claimed 24 lives and caused billions of dollars in damage. In addition to the tornadoes, large hail and damaging winds cause damage in many areas.

A brief tornado was reported via Spotter Network near Marlow. No damage was reported and the tornado lasted a very short time.

Several storm chasers and spotters observed a tornado that developed southeast of Marlow, and moved northeast to between Marlow and Bray. Minor damage to trees and power lines was reported. No injuries or fatalities occurred.

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

25 minutes of warning. NWS OUN issued a tornado warning for this county at 19:42 UTC, 25 minutes before the tornado touched down, in force until 20:15 UTC.

The county was under a tornado watch, issued at 18:10 UTC and running to 03:00 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 Moderate Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 19:58 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.

Halliburton Field Airport/Duncan (DUC), 17 km from the path, in the two hours either side.

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

The Norman radar (KTLX), 98 km away, was scanning. The volume nearest the touchdown began at 20:08 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 2013 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

35 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.