Unrated tornado, Grainola, Oklahoma, April 27, 2024

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

April 27, 2024

Touchdown

8:16 PM CDT (01:16 UTC)

Path length

0.1 miles (0.2 km)

Path width

75 yards (69 m)

Deaths

0

Injuries

0

County

Osage County

Touchdown point

36.959, -96.691

Lift-off point

36.959, -96.691

Record number

2404271916-01

7 damage points were recorded along this path by NWS ICT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 125 mph.

• Multi-vortex damage. This was a well constructed metal building that was anchored by bolts into concrete.
• Multi-vortex damage at the same farm. Each vortex was about 30 yards wide and hit 3 of the 5 buildings, two of them directly. This second building was concrete brick with anchored metal structure and wood roof, built closer to a house or sturdy garage than an out building, pole barn, or farm building.
• Tree damage, start of tornado
• First picture to the south west of point by 300 yards. Next pictures are north east of the point ranging from 100 to 300 yards

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

Severe thunderstorms developed during the afternoon of the 27th over central Oklahoma, along and ahead of the dry line, as a strong upper level low pressure system deepened into the Southern Rockies. Strong instability and strong wind shear over eastern Oklahoma supported organized severe thunderstorms, including supercells. The first round of storms affected portions of far northeastern Oklahoma during the early evening. By late evening, a line of severe thunderstorms moved into eastern Oklahoma from the west, with embedded supercells within the line, as well as a supercell ahead of the line. A strong tornado moved into Okfuskee County with the supercell ahead of the line. Multiple other tornadoes occurred as the storms moved through the area during the early morning hours of the 28th, along with damaging thunderstorm wind gusts. Isolated areas of flash flooding also occurred.||Another round of severe thunderstorms developed across eastern Oklahoma during the afternoon of the 28th. The strongest storms produced tornadoes, large hail to quarter size, and damaging wind gusts.

This brief tornado was observed and reported by storm chasers. The area where it likely occurred was surveyed by NWS Tulsa meteorologists, but it occurred over open country where no damage indicators could be found. Since no damage could be assessed, the tornado was rated EF-unknown.

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

15 minutes of warning. NWS TSA issued a tornado warning for this county at 01:01 UTC, 15 minutes before the tornado touched down, in force until 01:30 UTC.

The county was under a tornado watch, issued at 00:51 UTC and running to 06:12 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 01:02 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.

Winfield (WLD), 39 km from the path, in the two hours either side.

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

The Wichita radar (KICT), 102 km away, was scanning. The volume nearest the touchdown began at 01:19 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 2024 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

62 more were confirmed in the United States that day.

All 63 of them

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.