Tornadoes · United States · Tennessee · 2018
EF0 tornado, Athens Arpt, Tennessee, March 17, 2018
This EF0 tornado ran 0.4 miles across McMinn County on March 17, 2018, touching down at 7:23 PM EDT and reaching 100 yards wide. It killed nobody.
The rating scale
Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
EF065 to 85 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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.
The record
- Rating
- EF0
- Date
- March 17, 2018
- Touchdown
- 7:23 PM EDT (23:23 UTC)
- Lifted
- 7:24 PM EDT (23:24 UTC)
- On the ground
- 1 minutes
- Path length
- 0.4 miles (0.6 km)
- Path width
- 100 yards (91 m)
- Deaths
- 0
- Injuries
- 0
- County
- McMinn County
- Touchdown point
- 35.374, -84.576
- Lift-off point
- 35.373, -84.569
- Record number
- 1803171723-01
The damage survey
3 damage points were recorded along this path by NWS MRX, in the Damage Assessment Toolkit the survey teams carry. The highest wind the damage implies is 85 mph.
- combine this with the drone footage. RFD damage
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
What the Weather Service recorded
Thunderstorms developed ahead of an upper level system and surface cold front during the evening hours. Several of these storms produced large hail and wind damage. Funnel clouds were reported as a discrete supercell thunderstorm developed over Southeast Tennessee and moved into Southwest North Carolina. As this supercell moved into Monroe County, Tennessee, a weak tornado developed downing several trees and producing minor structural damage.
The tornado probably started somewhere on the eastern side of the Ridgewood Golf Club and tracked eastward. It went through a patch of trees where many softwoods were uprooted or snapped in the upper part of the trunk. The tornado exited the trees and dissipated a short distance over a field where only a couple of trees were damaged.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 22:38 UTC | 23:30 UTC | Severe Thunderstorm Warning | MRX |
| 23:21 UTC | 00:00 UTC | Severe Thunderstorm Warning | MRX |
| 23:24 UTC | 23:51 UTC | Severe Thunderstorm Warning | MRX |
| 23:29 UTC | 23:50 UTC | Tornado Warning | MRX |
| 23:59 UTC | 00:24 UTC | Severe Thunderstorm Warning | MRX |
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 forecast that day
The Storm Prediction Center had this point in a Marginal Risk. The outlook in force was issued at 19:56 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 air that afternoon
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.
Nashville Metro, TN (KBNA), 12:00Z
11.4 hours before the tornado, 201 km from the path. March 17, 2018.
- Mixed-layer CAPE
- 69 J/kg
- Mixed-layer CIN
- -106 J/kg
- Surface CAPE
- 2 J/kg
- Mixed-layer LCL
- 772 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 138 m²/s²
- 0-3 km storm-relative helicity
- 118 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
- 0-3 km lapse rate
- 5.3 K/km
Nashville Metro, TN (KBNA), 00:00Z
0.6 hours after it, 201 km from the path. March 18, 2018.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -86133 J/kg
- Surface CAPE
- 1 J/kg
- Mixed-layer LCL
- 2357 m above ground
- 0-6 km bulk shear
- 60 kt
- 0-1 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 59 m²/s²
- 0-3 km storm-relative helicity
- 175 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 8.1 K/km
The surface observations
Athens (MMI), 3 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 21:35 UTC | 73.4 | 55.4 | 200° 6 kt | 1009.5 | ||
| 21:55 UTC | 73.4 | 53.6 | 180° 7 kt | 1009.1 | ||
| 22:15 UTC | 71.6 | 55.4 | 190° 7 kt | 1008.8 | ||
| 22:35 UTC | 69.8 | 55.4 | 210° 7 kt | 1009.1 | ||
| 22:55 UTC | 69.8 | 53.6 | 200° 7 kt | 1009.1 | ||
| 23:15 UTC | 66.2 | 57.2 | 110° 5 kt | 1007.8 | ||
| 23:35 UTC | 62.6 | 59 | 330° 21 kt | 31 | 1009.5 | |
| 23:55 UTC | 60.8 | 57.2 | 0° 0 kt | 1009.5 | ||
| 00:15 UTC | 59 | 57.2 | 0° 0 kt | 1009.5 | ||
| 00:35 UTC | 57.2 | 57.2 | 0° 0 kt | 1009.5 | ||
| 00:55 UTC | 60.8 | 57.2 | 0° 0 kt | 1009.1 | ||
| 01:15 UTC | 59 | 57.2 | 0° 0 kt | 1009.1 |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Knoxville radar (KMRX), 138 km away, was scanning. The volume nearest the touchdown began at 23:25 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.
What was reported nearby
Local storm reports within 60 km of the path, in the three hours either side.
| Time (UTC) | Report | Where | County | Remark |
|---|---|---|---|---|
| 22:45 UTC | HAIL 0.75 | 1 Wsw Rockwood | Roane, TN | REPORTED AT 325 NORTH FRONT STREET ROCKWOOD TN. |
| 22:59 UTC | HAIL 0.5 | 1 E Rockwood | Roane, TN | REPORTED AT 174 COUNTRY CLUB ROAD ROCKWOOD TN. |
| 22:59 UTC | HAIL 0.5 | 1 E Rockwood | Roane, TN | |
| 23:05 UTC | HAIL 1.75 | 2 S Decatur | Meigs, TN | REPORTED BY PUBLIC. HAIL OCCURRED FOR 10 MINUTES. |
| 23:11 UTC | HAIL 0.88 | 5 Ssw Clear Water | Mcminn, TN | REPORTED AT COUNTY ROAD 112 WEST OF ATHENS TN. ALSO ESTIMATED 50 MPH WINDS. |
| 23:15 UTC | HAIL 1 | Lenoir City | Loudon, TN | QUARTER SIZE HAIL NEAR LENIOR CITY. |
| 23:30 UTC | HAIL 1 | Athens | Mcminn, TN | |
| 23:35 UTC | HAIL 1 | 2 Se Birchwood | Meigs, TN | REPORTED AT 787 RILEY LANE BIRCHWOOD TN. |
| 23:35 UTC | HAIL 1.5 | 3 N Mount Vernon | Monroe, TN | |
| 23:38 UTC | FUNNEL CLOUD | 5 W Etowah | Mcminn, TN | FUNNEL CLOUD FORMING AND MOVING EAST TOWARD ETOWAH. REPORTED AT COUNTY ROAD 750. |
| 23:40 UTC | FUNNEL CLOUD | 1 E Etowah | Mcminn, TN | FUNNEL CLOUD REPORTED IN EAST ETOWAH. |
| 23:48 UTC | HAIL 1.75 | 2 N Tasso | Bradley, TN | |
| 23:50 UTC | HAIL 0.75 | Charleston | Bradley, TN | |
| 00:00 UTC | HAIL 0.75 | 2 Ne Benton | Polk, TN | REPORTED AT 7200 HWY 411. |
| 00:20 UTC | HAIL 1.75 | Benton | Polk, TN | SEVERAL REPORTS OF GOLFBALL SIZE HAIL ACROSS POLK COUNTY, TN |
| 00:20 UTC | HAIL 1.75 | Benton | Polk, TN | SEVERAL REPORTS OF GOLFBALL SIZE HAIL ACROSS POLK COUNTY, TN. |
| 00:53 UTC | HAIL 0.88 | Lenoir City | Loudon, TN |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2018 tornado in TennesseeEvery tornado in Tennessee since 1950Warnings in force in Tennessee nowThe forecast where you are
The other tornadoes of March 17, 2018
4 more were confirmed in the United States that day.
What this means
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.
Sources
NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.