EF3 tornado, Bartlebaugh to Conasauga, Tennessee, March 2, 2012

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 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 mphthis tornado

   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

EF3

Date

March 2, 2012

Touchdown

12:41 PM EST (17:41 UTC)

Lifted

1:35 PM EST (18:35 UTC)

On the ground

54 minutes

Path length

41.0 miles (66.0 km)

Path width

400 yards (366 m)

Deaths

0

Injuries

44

Property damage

$35 million

Counties

Hamilton, Bradley, Polk and McMinn counties

Touchdown point

35.128, -85.161

Lift-off point

35.313, -84.472

Record number

1203021141-01

A deepening low pressure system moved northeast from the Mid Mississippi Valley through the Great Lakes initially driving a warm front northward through the Southern Appalachian region during the afternoon. The associated cold front swept across the area late Friday night. A one hundred knot upper level jet positioned over a 50 knot low level jet resulted in a strongly sheared environment. The intense shear and moderate instability produced an atmosphere conducive to long-lived, discrete, supercell thunderstorms. A total of 9 tornadoes ranging in intensity from EF-0 to EF-3 produced widespread damage and nearly 50 injuries to East Tennessee residents in the path of the storms.

Harrison Tornado--Segment #1. This tornado was the strongest of the day in the southeastern U.S.--rated a strong EF3 with 165 MPH maximum winds. The tornado formed on a northward-extending peninsula in Lake Chickamauga, just north of the Booker T. Washington State Park. At this point, the tornado downed a few trees and caused some light structural damage. ||The tornado then moved ENE and crossed Waconga Bay. On the east side of the bay the tornado smashed a very large marina--Island Cove Marina--causing $6,000,000 in damage. The tornado was a strong EF1 with about 110 mph winds. The tornado track so far was about 2 miles long.||The tornado continued to strengthen as it went on land, crossed State Highway 58 and quickly strengthed to EF2. Over the next two miles the path was a consistent EF2 to EF3 through several neighborhoods. The worst damage was found along Short Tail Springs Road, Woodland Bay Drive and Davis Mill Circle. The most intense damage was found near the intersection of Short Tail Springs Road and Woodland Bay Drive where many residences suffered EF3 damage with one residence wiped out. Across, to the south of Short Tail Springs Road, an entire forest of trees was downed. ||By the time the tornado left this neighborhood it was mainly EF2, went across another couple of inlets of the lake, and emerged as an EF1 by the time it crossed Ooltewah-Georgetown Rd, (CR 1145). From here to the Bradley County line, the tornado continued to the ENE through rural areas oscillating between EF1 and low-end EF2 damage. The tornado continued into and across Bradley, northern Polk County, and into southern McMinn County. The total pathlength was 41 miles.||In Hamilton County, there were 30 injuries, including 6 serious injuries, but no fatalities. There were 80+ homes destroyed, 85+ homes with major damage with a total of 260+ with damage to about $20 Million. Damage to public infrastructure totaled $2.1 Million. Initial overall estimates exceeded $28 Million.||A Presidential Disaster was declared for this area. EMA officials were amazed there were no deaths after seeing the intensity at some locations.||Note: The tornado had two turns in Hamilton County--a slight left turn at 35.1367/-85.1121 and another slight left turn (even farther left) at 35.1585/-85.0352.

Harrison Tornado - Segment #2. The Harrison Tornado entered western Bradley County near the saddlepoint along a ridgeline named Mahan Gap. It roughly followed Harrison Pike ENE for about 4 miles, until the highway turned off to the south. The tornado continued into the northern parts of the city of Cleveland and then across the remainder of the county into Polk County. ||The tornado was near its strongest in the first mile or two into Bradley County where it downed vast swaths of trees along the highway. The maximum estimated winds were 130 MPH, making it a high EF2 at its peak. This area was very rugged with no houses near the county line.||Overall there were 46 houses that were damaged, included 5 destroyed, and 11 with major damage, as well as 41 other homes that were affected. Two businesses and three barns were destroyed. Overall monetary damages totaled $3.2 Million damage to homes, $640K to business, and $300K to Utilities, totaling to almost $4 Million. There were 7 injuries; all treated and released.||The last few miles in Bradley County the tornado weakened to EF1 and then to a minimal EF0 as it crossed the Hiwassee River into Polk County.||Note: this tornado had the following turns: slightly to the left at 35.2002/-84.8521 and sharper to the right (almost due east) at 35.2265/-84.8051, then continued to the county line.

Harrison Tornado - Segment #4. The Harrison Tornado continued to intensify again as it crossed from Polk into McMinn County. It was an EF1 at 100 MPH when it crossed the county line but quickly elevated to an EF2, and reached its maximum strength only about 1 1/2 miles inside McMinn County as an EF2 at 130 MPH where it caused heavy damage to several rural homes.||The tornado then continued to the northeast slowly weakening, crossed U.S. Highway 411, then started to climb the terrain on the north end of Starr Mountain where it dissipated. This storm went on to produce another tornado in Monroe County.||In McMinn County 37 homes and mobile homes were damaged. Four homes and seven mobile homes were destroyed. Property damages totaled about $2 Million. There were 7 injuries.||This tornado ended in McMinn County, but crossed parts of four counties, had an over pathlength of 41 miles and caused 44 injuries.

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

25 minutes of warning. NWS MRX issued a tornado warning for this county at 17:16 UTC, 25 minutes before the tornado touched down, in force until 18:00 UTC.

The county was under a tornado watch, issued at 15:27 UTC and running to 20:19 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 Moderate Risk, with a 0.15 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 16:31 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), 120 km away, was scanning. The volume nearest the touchdown began at 17:39 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 2012 tornado in TennesseeEvery tornado in Tennessee since 1950Warnings in force in Tennessee nowThe forecast where you are

69 more were confirmed in the United States that day.

All 70 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.