EF2 tornado, Greenbrier to Oakwood College, Alabama, May 6, 2009

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

May 6, 2009

Touchdown

8:59 AM CDT (13:59 UTC)

Lifted

9:17 AM CDT (14:17 UTC)

On the ground

18 minutes

Path length

10.9 miles (17.5 km)

Path width

75 yards (69 m)

Deaths

0

Injuries

0

Property damage

$1.0 million

Counties

Limestone and Madison counties

Touchdown point

34.683, -86.819

Lift-off point

34.777, -86.665

Record number

0905060759-01

Strong thunderstorms erupted around Midnight on the 6th in northwest Alabama and tracked across portions of north Alabama. The storms produced one to three inches of rainfall in parts of Lawrence, Morgan, Cullman and Marshall Counties resulting in a few instances of flash flooding. Following this first round of thunderstorms, a vigorous quasi-linear convective system (QLCS) advanced eastward from northern Mississippi into northwest Alabama before sunrise. This system strengthened as it encountered increasing instability. Given high amounts of low level wind shear, a break in the line resulted as a strong comma head / mesocyclone developed. This storm evolved into its own miniature supercell spawning three tornadoes along its track from eastern Lawrence through Morgan, Limestone and Madison Counties. The tornado in Limestone and Madison County produced up to EF2 damage along its 10.9 mile track, narrowly missing an elementary school, high school, and two churches in Madison. Other reports of thunderstorm wind damage were received with these storms.

A tornado touched down along Segers Road in eastern Limestone county, snapping and uprooting numerous large trees. A tree fell on a mobile home on Hardiman Road and split it in half. Peak wind speed was estimated at 115 mph with a path width of 75 yards.

The tornado continued northeast into Madison County. Significant tree damage occurred in several subdivisions along County Line Road, Mill Road, Browns Ferry, Wall Triana Highway, Hughes Road and Slaughter Road. Windows were blown out of several houses in the Huntington Chase subdivision along with significant roof damage. A large attached garage was completely flattened along Browns Ferry Road and roof damage was observed in the Bridgefield subdivision. Several residents of the Bridgefield subdivision noted that they received the tornado warning and took cover before the storm hit. The tornado tracked through the parking lot of West Madison Elementary School, knocking large pine trees down onto apartment buildings and a home adjacent to the school. The tornado then tracked through the Wellington subdivision producing tree and roof damage. Sporadic damage persisted as the tornado moved northeast across Hughes Road, atop Rainbow Mountain, and across Slaughter Road into northwest Huntsville and the Providence development. The tornado finally lifted near Research Park and Plummer Road.

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

4 minutes of warning. NWS HUN issued a tornado warning for this county at 13:55 UTC, 4 minutes before the tornado touched down, in force until 14:15 UTC.

The county was under a severe thunderstorm watch, issued at 09:05 UTC and running to 15:00 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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 12:47 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 Northeast Alabama radar (KHTX), 64 km away, was scanning. The volume nearest the touchdown began at 13:57 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 2009 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

21 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.