Unrated tornado, Felt to Boise City, Oklahoma, May 30, 2021

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 mph

   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. Unratedthis tornado

   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

Unrated

Date

May 30, 2021

Touchdown

6:44 PM CDT (23:44 UTC)

Lifted

6:45 PM CDT (23:45 UTC)

On the ground

1 minutes

Path length

0.5 miles (0.8 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

County

Cimarron County

Touchdown point

36.590, -102.540

Lift-off point

36.584, -102.535

Record number

2105301744-01

Persistent low level winds out of the east brought substantial moisture to the region and contributed to severe supercell thunderstorm development as an upper level disturbance approached from the southwest. Large hail, severe wind gusts, flooding rains and tornadoes all occurred on this day. An nearly stationary outflow boundary provided strong turning in the low level wind fields that created additional wind shear which was instrumental in development of several tornadoes with the supercells that tracked near or along the boundary. A total of 13 tornadoes were confirmed in what turned out to be the highest tornado producing event of the season, although most of these were very short lived, weak, and produced little damage and/or impact. Seven tornadoes occurred in Cimarron County, mainly in the vicinity of Felt, all of which occurred over open land but were well documented by chasers. Six tornadoes occurred in Dallam and Sherman Counties, all of which were rated EF-0 or were unable to be rated due to a lack of damage indicators. Additionally, heavy rainfall occurred in many locations given the large amount of moisture in place, with flash flooding occurring in Amarillo, Canyon, and Wellington. Some locations received more than 4 inches of rainfall.

Multiple storm chasers reported and recorded video of a tornado |around 17 miles southwest of Boise City. This tornado began at the|same time as one to the north within the original circulation. |The tornado remained in open grassland and did not encounter any |damage indicators.

Multiple storm chasers reported and recorded video of a very|brief tornado a around 4 miles northeast of Felt. This tornado|was within the original storm mesocyclone near Highway 412. The|storm briefly had two tornadoes as a new tornado developed on the|south side of the storm and became the dominant circulation. The|tornado remained in open grassland and did not encounter any|damage indicators. Path was estimated based on reports and video.

Multiple storm chasers reported and recorded video of a brief |tornado around 10 miles south of Boise City. The tornado remained |in open grassland and did not encounter any damage indicators.

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

30 minutes of warning. NWS AMA issued a tornado warning for this county at 23:14 UTC, 30 minutes before the tornado touched down, in force until 00:00 UTC.

The county was under a tornado watch, issued at 21:42 UTC and running to 02:20 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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:43 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.

Clayton (CAO), 57 km from the path, in the two hours either side.

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

The Amarillo radar (KAMA), 168 km away, was scanning. The volume nearest the touchdown began at 23:42 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 2021 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

17 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.