EF1 tornado, North Four Corners, Kentucky, December 11, 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 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

December 11, 2021

Touchdown

1:06 AM EST (06:06 UTC)

Lifted

1:08 AM EST (06:08 UTC)

On the ground

2 minutes

Path length

1.9 miles (3.1 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

County

Hardin County

Touchdown point

37.775, -86.138

Lift-off point

37.786, -86.107

Record number

2112110006-01

21 damage points were recorded along this path by NWS LMK, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 105 mph.

• Based on photos sent in by resident
• From EM damage point on Deckard School Rd. Time estimated based on radar data.
• EM damage report of fence washed out and trees down on fences. Not sure if it was a branch or uprooted, so went on the low side of the latter. Time estimated based on radar.

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

Strong southern winds brought warm temperatures and plenty of moisture into an environment of strong wind shear ahead of an advancing cold front. This resulted in unusually warm temperatures for a December day and the ingredients to produce a historic tornado outbreak and flash flooding. This included multiple long track tornadoes. Central Kentucky saw 18 tornadoes that injured 96 and killed 18. An additional death occurred in a flash flood.

An EF-1 tornado touched down near Long Hollow Road and snapped or uprooted several trees which resulted in the road being blocked and powerlines coming down. The tornado continued to the northeast and did sporadic wind damage. It approached Rineyville-Big Springs Road where it hit a couple of farm buildings and resulted in wall and roof damage. The width of the tornado was fairly narrow as a nearby farm building was untouched/unharmed. The tornado continued to race off to the northeast and caused sporadic tree damage. The tornado eventually lifted in a heavily wooded area near the Cochran family farm.

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

15 minutes of warning. NWS LMK issued a tornado warning for this county at 05:51 UTC, 15 minutes before the tornado touched down, in force until 06:30 UTC.

The county was under a tornado watch, issued at 00:22 UTC and running to 07:29 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 Marginal Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 05:48 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.

The Louisville radar (KLVX), 27 km away, was scanning. The volume nearest the touchdown began at 06:07 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 KentuckyEvery tornado in Kentucky since 1950Warnings in force in Kentucky nowThe forecast where you are

37 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.