EF0 tornado, Citronelle, Alabama, April 15, 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

April 15, 2011

Touchdown

10:05 PM CDT (03:05 UTC)

Lifted

10:09 PM CDT (03:09 UTC)

On the ground

4 minutes

Path length

1.2 miles (2.0 km)

Path width

80 yards (73 m)

Deaths

0

Injuries

0

Property damage

$30,000

County

Mobile County

Touchdown point

31.096, -88.253

Lift-off point

31.097, -88.232

Record number

1104152105-01

18 damage points were recorded along this path by NWS MOB, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF3. The highest wind the damage implies is 160 mph.

• trees topped with several large limbs downed.
• Several trees down with trunks snapped in half.
• 2 residences suffered significant roof damage with 20 to 40 percent of roof removed to the rafters on north facing slopes. Numerous trees down or snapped in half with an outbuilding destroyed.
• Home was moved off foundation with roof totally removed and all but 1 exterior wall missing. Only a few small interior rooms remained intact.

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

Numerous supercell thunderstorms developed in the late morning through the evening hours across Mississippi and Alabama. A series of long track tornadic supercell thunderstorms moved out of southeast Mississippi in the late morning, and crossed southwest Alabama in the late morning through the afternoon and evening hours. In southwest Alabama, the tornadoes missed the larger populated towns and communities, but did produce significant damage to numerous homes in rural areas. Several injuries were reported with 3 fatalities in Deer Park, Alabama (Washington County) from an EF-3 tornado during the early evening hours. Widespread damage to timber along several 200 to 600 yard-wide tornado paths resulted in significant losses to the timber industry. The Alabama Forestry Commission estimated timber losses in southwest Alabama to be near 7.3 million dollars.

Brief tornado touchdown in the city of Citronelle. Roofs were damaged on a few single-wide manufactured homes with minor roof damage to a few single-family wood frame homes. Some trees were twisted off near the tops. A section of metal roofing was removed from one unit of the Wahoo Apartments on South Center Street.

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

0 minutes of warning. NWS MOB issued a tornado warning for this county at 03:05 UTC, 0 minutes before the tornado touched down, in force until 03:39 UTC.

The county was under a tornado watch, issued at 00:48 UTC and running to 05:50 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 Slight Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 00:58 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.

Mobile/Bates Field (MOB), 45 km from the path, in the two hours either side.

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

The Mobile radar (KMOB), 46 km away, was scanning. The volume nearest the touchdown began at 03:03 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

74 more were confirmed in the United States that day.

All 75 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.