Tornadoes · United States · Tennessee · 2011

EF1 tornado, Signal Mtn to Red Bank, Tennessee, February 28, 2011

From Signal Mtn to Red Bank, this EF1 tornado ran 2.6 miles across Hamilton County on February 28, 2011, touching down at 2:30 PM EST and reaching 150 yards wide. It killed nobody, and did $5.0 million of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  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 mphthis tornado

    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.

The record

Rating
EF1
Date
February 28, 2011
Touchdown
2:30 PM EST (19:30 UTC)
Lifted
2:45 PM EST (19:45 UTC)
On the ground
15 minutes
Path length
2.6 miles (4.2 km)
Path width
150 yards (137 m)
Deaths
0
Injuries
0
Property damage
$5.0 million
County
Hamilton County
Touchdown point
35.179, -85.280
Lift-off point
35.179, -85.280
Record number
1102281330-01

What the Weather Service recorded

A strong storm system moved through the area on February 28th, producing three tornadoes in southeast Tennessee and widespread flooding in east Tennessee. One person died.

An EF1 tornado touched down at Signal Mountain. The path length was 2.2 miles and the path width from 60 to 90 yards. The max wind of 90 mph caused damage to an estimated 25 homes and numerous trees were downed.

An EF1 tornado touched down two miles north of Red Bank. The path length was 2.6 miles with an average path width from 85 to 100 yards and a maximum width of 150 yards. The maximum wind speed was 90 mph which damage at least 20 homes along with numerous trees downed by the wind.

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

The warnings

42 minutes of warning. NWS MRX issued a tornado warning for this county at 18:48 UTC, 42 minutes before the tornado touched down, in force until 19:30 UTC.

The county was under a tornado watch, issued at 18:42 UTC and running to 21:50 UTC.

Issued (UTC)ExpiredProductOffice
12:01 UTC18:42 UTCTornado WatchMRX
18:42 UTC21:50 UTCTornado WatchMRX
18:43 UTC19:15 UTCSevere Thunderstorm WarningMRX
18:48 UTC19:30 UTCTornado WarningMRX
19:22 UTC20:00 UTCTornado WarningMRX
19:33 UTC20:15 UTCSevere Thunderstorm WarningMRX

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 forecast that day

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 16:30 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.

What forecasters said that day

The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Morristown, TN wrote its last area forecast discussion before the tornado touched down at Feb 28, 12:59 PM EST, 1 hour 31 minutes earlier.

Area forecast discussion, Feb 28, 12:59 PM EST, 1 hour 31 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1259 PM EST MON FEB 28 2011

.AVIATION...COLD FRONT TRACKING THROUGH THE AREA BRINGING IFR/MVFR
CONDITIONS...THUNDERSTORMS AND STRONG GUSTY SOUTHWEST WINDS TO ALL
SITES EARLY IN THE TAF PERIOD. WINDS SHOULD DECREASE AND SWITCH TO
THE NORTHWEST IN THE EVENING HOURS.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR THE FOLLOWING
     ZONES: CHEROKEE...CLAY.

TN...FLOOD WATCH UNTIL 10 PM EST THIS EVENING FOR THE FOLLOWING
     ZONES: ANDERSON...CAMPBELL...CLAIBORNE...GRAINGER...
     HAMBLEN...HANCOCK...HAWKINS...MORGAN...NORTHWEST CARTER...
     NORTHWEST GREENE...SCOTT TN...SULLIVAN...UNION...WASHINGTON
     TN.

     WIND ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR THE
     FOLLOWING ZONES: ANDERSON...BLEDSOE...BLOUNT SMOKY
     MOUNTAINS...CAMPBELL...CLAIBORNE...COCKE SMOKY MOUNTAINS...
     EAST POLK...JOHNSON...MARION...MORGAN...SCOTT TN...
     SEQUATCHIE...SEVIER SMOKY MOUNTAINS...SOUTHEAST CARTER...
     SOUTHEAST GREENE...SOUTHEAST MONROE...UNICOI...UNION.

VA...FLOOD WATCH UNTIL 10 PM EST THIS EVENING FOR THE FOLLOWING
     ZONES: LEE...RUSSELL...SCOTT...WASHINGTON...WISE.

     WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR THE FOLLOWING
     ZONES: LEE...RUSSELL...SCOTT...WASHINGTON...WISE.

&&

GH
Hazardous weather outlook, Feb 28, 4:36 AM EST, 9 hours 54 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
436 AM EST MON FEB 28 2011

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-010945-
CHEROKEE-CLAY-SCOTT TN-CAMPBELL-CLAIBORNE-HANCOCK-HAWKINS-
SULLIVAN-JOHNSON-MORGAN-ANDERSON-UNION-GRAINGER-HAMBLEN-
NORTHWEST COCKE-COCKE SMOKY MOUNTAINS-NORTHWEST GREENE-
SOUTHEAST GREENE-WASHINGTON TN-UNICOI-NORTHWEST CARTER-
SOUTHEAST CARTER-ROANE-LOUDON-KNOX-JEFFERSON-NW BLOUNT-
BLOUNT SMOKY MOUNTAINS-NORTH SEVIER-SEVIER SMOKY MOUNTAINS-
SEQUATCHIE-BLEDSOE-RHEA-MEIGS-MCMINN-NORTHWEST MONROE-
SOUTHEAST MONROE-MARION-HAMILTON-BRADLEY-WEST POLK-EAST POLK-LEE-
WISE-SCOTT-RUSSELL-WASHINGTON-
436 AM EST MON FEB 28 2011 /336 AM CST MON FEB 28 2011/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST NORTH
CAROLINA...EAST TENNESSEE AND SOUTHWEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

A SLIGHT TO MODERATE RISK OF SEVERE THUNDERSTORMS EXISTS TODAY FOR
THE REGION...INCLUDING ISOLATED TORNADOES.  STRONG AND GUSTY WINDS
WILL ALSO OCCUR AHEAD OF THESE STORMS AND AN ASSOCIATED COLD FRONT
...MAINLY FOR ELEVATIONS ABOVE 2500 FEET WHERE A WIND ADVISORY IS
IN EFFECT.  LOCALLY HEAVY RAINS COULD CAUSE FLOODING OR FLASH
FLOODING OVER PARTS OF NORTHEAST TENNESSEE INTO SOUTHWESTERN
VIRGINIA.

FOR MORE DETAILS ON THESE HAZARDS...SEE OUR LATEST SPECIAL WEATHER
STATEMENT...FLOOD WATCH...OR WIND ADVISORY PRODUCTS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

TRANQUIL WEATHER RETURNS FOR TUESDAY THROUGH FRIDAY...WITH THE NEXT
CHANCE OF THUNDERSTORMS ON SATURDAY.

NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE NEEDED LATER THIS MORNING INTO THE EARLY
EVENING HOURS.

TG

In the hours before

Local storm report, Feb 28, 2:14 PM EST, 16 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
214 PM EST MON FEB 28 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0155 PM     FLOOD            MORRISTOWN              36.21N 83.30W
02/28/2011                   HAMBLEN            TN   NWS EMPLOYEE

            FLOODING ALONG PANTHER CREEK ROAD.

&&
Local storm report, Feb 28, 2:16 PM EST, 14 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
216 PM EST MON FEB 28 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0150 PM     FLOOD            JEFFERSON CITY          36.12N 83.49W
02/28/2011                   JEFFERSON          TN   BROADCAST MEDIA

            FLOODING REPORTED COUNTYWIDE.

&&
Local storm report, Feb 28, 2:17 PM EST, 13 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
217 PM EST MON FEB 28 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0150 PM     FLOOD            HARRIMAN                35.93N 84.56W
02/28/2011                   ROANE              TN   BROADCAST MEDIA

            FLOODING REPORTED COUNTYWIDE.

&&
Local storm report, Feb 28, 2:18 PM EST, 12 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
218 PM EST MON FEB 28 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0150 PM     FLOOD            WARTBURG                36.10N 84.59W
02/28/2011                   MORGAN             TN   BROADCAST MEDIA

            FLOODING REPORTED COUNTYWIDE.

&&
Local storm report, Feb 28, 2:20 PM EST, 10 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
220 PM EST MON FEB 28 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0150 PM     FLOOD            KNOXVILLE               35.97N 83.95W
02/28/2011                   KNOX               TN   BROADCAST MEDIA

            FLOODING REPORTED COUNTYWIDE.

&&
Local storm report, Feb 28, 2:30 PM EST, 0 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
230 PM EST MON FEB 28 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0200 PM     TSTM WND DMG     1 N JASPER              35.07N 85.63W
02/28/2011                   MARION             TN   EMERGENCY MNGR

            FEW TREES DOWN.

&&

The air that afternoon

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.

Nashville Metro, TN (KBNA), 12:00Z

7.5 hours before the tornado, 159 km from the path. February 28, 2011.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 2011-02-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 948 joules per kilogram, CIN -5, lifted condensation level 795 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Nashville Metro, TN at 12:00Z on 2011-02-28The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 369 square meters per square second, 0 to 6 km bulk shear 65 knots.1939587897117136Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
948 J/kg
Mixed-layer CIN
-5 J/kg
Surface CAPE
843 J/kg
Mixed-layer LCL
795 m above ground
0-6 km bulk shear
65 kt
0-1 km bulk shear
39 kt
0-1 km storm-relative helicity
369 m²/s²
0-3 km storm-relative helicity
404 m²/s²
Significant tornado parameter
2.6
Supercell composite
9.4
0-3 km lapse rate
5.8 K/km

Open this sounding in Storm Lab

Nashville Metro, TN (KBNA), 00:00Z

4.5 hours after it, 159 km from the path. March 1, 2011.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 2011-03-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -88448, lifted condensation level 650 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Nashville Metro, TN at 00:00Z on 2011-03-01The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity -181 square meters per square second, 0 to 6 km bulk shear 77 knots.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-88448 J/kg
Surface CAPE
7 J/kg
Mixed-layer LCL
650 m above ground
0-6 km bulk shear
77 kt
0-1 km bulk shear
22 kt
0-1 km storm-relative helicity
-181 m²/s²
0-3 km storm-relative helicity
-12 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.5 K/km

Open this sounding in Storm Lab

The radar

The Northeast Alabama radar (KHTX), 78 km away, was scanning. The volume nearest the touchdown began at 19:29 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
19:00 UTCTSTM WND DMG1 N JasperMarion, TNFEW TREES DOWN.
19:00 UTCTORNADO1 W South PittsburgMarion, TNEF0. MAXIMUM WIND SPEED 70 MPH. PATH WIDTH 20 YARDS. PATH LENGTH 0.1 MILE. TREES DOWN.
19:25 UTCTSTM WND DMGChattanoogaHamilton, TNFEW TREES DOWN NEAR INTERSECTION OF HOOKER AND WILSON ROADS.
19:25 UTCTORNADOSignal MountainHamilton, TNEF1. MAX WIND SPEED 90 MPH. PATH LENGTH 2.2 MILES. PATH WIDTH FROM 60 TO 90 YARDS. NUMEROUS TREES DOWN. ESTIMATED 25 HOMES WITH MINOR DAMAGE.
19:30 UTCTSTM WND DMGRed BankHamilton, TNFEW TREES DOWN ON A HOUSE.
19:30 UTCTSTM WND DMGSignal MountainHamilton, TNNUMEROUS TREES AND POWER LINES DOWN AND 8 HOMES WITH DAMAGE RANGING FROM MINOR TO MAJOR BETWEEN SIGNAL MOUNTAIN AND REDBANK.
19:30 UTCTORNADO2 N Red BankHamilton, TNEF1. MAX WIND SPEED 85 MPH. PATH LENGTH 2.6 MILES. AVERAGE PATH WIDTH 85 TO 100 YARDS WITH A MAXIMUM WIDTH OF 150 YARDS. NUMEROUS TREES DOWN. AT LEAST 10 HOMES WITH DAMAGE.
19:40 UTCTSTM WND DMG5 Se ClevelandBradley, TNFEW TREES AND A FLAG POLE DOWN.
19:40 UTCTSTM WND DMGDaytonRhea, TNTWO TREES DOWN.
19:45 UTCHAIL 1ClevelandBradley, TN
19:53 UTCHAIL 0.53 N CiscoMurray, GADIME SIZE HAIL REPORTED BY US FOREST SERVICE ON THE STATE LINE NORTH OF CISCO.
20:00 UTCTSTM WND DMG10 S BentonPolk, TN*** 1 FATAL *** 1 FATALITY REPORTED 10 MILES SOUTH OF BENTON IN THE OLD FORT AREA ON LADD SPRINGS RD. TREE FELL ON A MOBILE HOME AND KILLED A 75 YEAR OLD MAN.
20:05 UTCTSTM WND DMG3 Sw BentonPolk, TNNUMEROUS TREES AND POWER LINES DOWN IN OCOEE.
20:05 UTCTSTM WND DMG6 Ssw BentonPolk, TNNUMEROUS TREES AND POWER LINES DOWN.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2011 tornado in TennesseeEvery tornado in Tennessee since 1950Warnings in force in Tennessee nowThe forecast where you are

The other tornadoes of February 28, 2011

25 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
February 2812:03 AM CSTEF0Washington, IL2.850
February 2812:08 AM CSTEF2Washington, IL2.3100
February 2812:27 AM CSTEF2Fayette, IL1.390
February 2812:32 AM CSTEF1Fayette, IL0.110
February 2812:33 AM CSTEF2Fayette, IL0.150
February 281:36 AM CSTEF1Gibson, IN23.3250$150,000
February 281:51 AM CSTEF2Gibson, IN22.0550$600,000
February 283:10 AM ESTEF0Pike, IN1.9200$150,000
February 283:19 AM ESTEF2Dubois, IN14.22251$500,000
February 283:29 AM CSTEF1Clark, IN to KY3.0100$7,000
February 284:43 AM ESTEF1Oldham, KY1.275
February 284:59 AM ESTEF3Henry, KY2.31501$500,000
February 286:00 AM ESTEF1Fairfield, OH2.475$100,000
February 286:49 AM ESTEF1Lincoln, KY8.7250$100,000
February 287:37 AM ESTEF1Wolfe, KY0.3100$75,000
February 2812:18 PM CSTEF2Franklin, TN16.160014$40,000
February 2812:18 PM CSTEF1Madison, AL3.9200$30,000
February 281:00 PM CSTEF0Marion, TN0.020$20,000
February 282:25 PM ESTEF1Hamilton, TN2.290$1.3 million
February 283:53 PM CSTEF0Talladega, AL0.350$8,000
February 285:02 PM ESTEF0Greenville, SC1.550
February 285:05 PM CSTEF0Autauga, AL8.9200$77,000
February 285:28 PM CSTEF0Chambers, AL1.930$45,000
February 285:37 PM CSTEF1Lowndes, AL5.0200$60,000
February 287:24 PM ESTEF1Newberry, SC3.4100$120,000

What this means

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.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.