EF0 tornado, Graham, Alabama, December 21, 2011

1. EF065 to 85 mphthis tornado

   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. 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

EF0

Date

December 21, 2011

Touchdown

12:32 PM CST (18:32 UTC)

Lifted

12:33 PM CST (18:33 UTC)

On the ground

1 minutes

Path length

0.3 miles (0.4 km)

Path width

88 yards (80 m)

Deaths

0

Injuries

0

Property damage

$25,000

County

Randolph County

Touchdown point

33.421, -85.320

Lift-off point

33.422, -85.316

Record number

1112211232-01

A cold front pushed into Central Alabama during the day on Wednesday, December 21, 2011, eventually stalling northeast to southwest, bisecting the forecast area in half. In a marginally unstable airmass ahead of the front (effective bulk shear around 50 kts and CAPE between 500-1000 J/kg), strong storms developed. As low level shear increased, several storms showed signs of rotation, with one producing damage near the Georgia state line in Randolph County.

After a review of damage, eye witness accounts, and analysis of Dual-Pol radar data from KFFC, it was determined that damage in northeastern Randolph county was a result of a brief EF-0 tornado. The EF-0 tornado with winds of 70 mph briefly touched down near Sewell, along County Road 87, south of County Road 438. One home and half a dozen outbuildings sustained roof damage, as metal roofing was peeled off and tossed up to one half mile downwind. Minor tree damage was also noted. Two witnesses reported a funnel cloud in the area, but due to terrain were unable to confirm whether the circulation extended to the ground.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

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 General Thunderstorms Risk. The outlook in force was issued at 16:26 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 Atlanta radar (KFFC), 70 km away, was scanning. The volume nearest the touchdown began at 18:30 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 AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

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.