EF2 tornado, Moore Crossing to Guild, Tennessee, April 27, 2011

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 mphthis tornado

   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

EF2

Date

April 27, 2011

Touchdown

5:21 PM CDT (22:21 UTC)

Lifted

5:31 PM CDT (22:31 UTC)

On the ground

10 minutes

Path length

10.0 miles (16.1 km)

Path width

800 yards (732 m)

Deaths

0

Injuries

0

Property damage

$30,000

County

Marion County

Touchdown point

34.985, -85.638

Lift-off point

35.070, -85.500

Record number

1104271621-01

10 damage points were recorded along this path by NWS FFC and NWS HUN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF4. The highest wind the damage implies is 170 mph.

• End point of Section-Flat Rock, GA EF-4 Tornado in Alabama.
• End point of Bridgeport EF-4 Tornado.

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

Favorable atmospheric conditions resulted in a deadly tornado outbreak across east Tennessee on the 27th. The thunderstorms produced more than 50 tornadoes across the east Tennessee area with 32 deaths and more than 200 injured. The tornadoes produced from light to heavy damage to hundreds of homes and businesses. Hail as large as baseballs was also reported.

A NWS storm survey reported an EF2 tornado continued its path from Alabama and entered the border near Lakeview Drive and moved northeast across Nickajack Lake near Haletown and ended near the Tennessee River. It had path width of 800 yards and a path length of 10 miles. The max wind of 115 mph downed numerous trees.

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

25 minutes of warning. NWS HUN issued a tornado warning for this county at 21:56 UTC, 25 minutes before the tornado touched down, in force until 22:30 UTC.

The county was under a tornado watch, issued at 18:45 UTC and running to 02:33 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 High Risk, with a 0.30 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 19:12 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.

Chattanooga/Lovell (CHA), 33 km from the path, in the two hours either side.

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

The Northeast Alabama radar (KHTX), 48 km away, was scanning. The volume nearest the touchdown began at 22:16 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 2011 tornado in TennesseeEvery tornado in Tennessee since 1950Warnings in force in Tennessee nowThe forecast where you are

209 more were confirmed in the United States that day.

All 210 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.