Tornadoes · United States · Florida · 2011

EF0 tornado, Alva, Florida, January 25, 2011

This EF0 tornado ran 0.3 miles across Lee County on January 25, 2011, touching down at 7:40 PM EST and reaching 50 yards wide. It killed nobody, and did $100,000 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 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.

The record

Rating
EF0
Date
January 25, 2011
Touchdown
7:40 PM EST (00:40 UTC)
Lifted
7:42 PM EST (00:42 UTC)
On the ground
2 minutes
Path length
0.3 miles (0.5 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$100,000
County
Lee County
Touchdown point
26.716, -81.600
Lift-off point
26.717, -81.595
Record number
1101251840-01

What the Weather Service recorded

A low pressure system over the northeast Gulf of Mexico moved northeast across northern Florida and sent a squall line through the area. The thunderstorms brought damaging winds, large hail, minor flooding and a few weak tornadoes.

Six mobile homes were damaged or destroyed near Alva along Basil, Dill, Cork, and Elder Streets. The mobile homes suffered porch damage, broken screens, roof damage, and a carport was destroyed. Emergency Management found a narrow path of damage, and time is estimated off of radar.

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

The warnings

22 minutes of warning. NWS TBW issued a tornado warning for this county at 00:18 UTC, 22 minutes before the tornado touched down, in force until 00:45 UTC.

The county was under a tornado watch, issued at 23:18 UTC and running to 02:00 UTC.

Issued (UTC)ExpiredProductOffice
15:00 UTC23:00 UTCLake Wind AdvisoryTBW
18:00 UTC04:35 UTCHigh Surf AdvisoryTBW
23:18 UTC02:00 UTCTornado WatchTBW
00:18 UTC00:45 UTCTornado WarningTBW
01:02 UTC01:45 UTCSevere Thunderstorm WarningTBW
14:48 UTC21:00 UTCLake Wind AdvisoryTBW

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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:25 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 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.

Tampa Bay, FL (KTBW), 12:00Z

11.3 hours after it, 136 km from the path. January 26, 2011.

Skew-T log-pSkew-T log-p diagram, Tampa Bay, FL at 12:00Z on 2011-01-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 48 joules per kilogram, CIN -103, lifted condensation level 623 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, Tampa Bay, FL at 12:00Z on 2011-01-26The 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 127 square meters per square second, 0 to 6 km bulk shear 60 knots.1939587897117Sfc1 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
48 J/kg
Mixed-layer CIN
-103 J/kg
Surface CAPE
41 J/kg
Mixed-layer LCL
623 m above ground
0-6 km bulk shear
60 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
127 m²/s²
0-3 km storm-relative helicity
262 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1
0-3 km lapse rate
4.6 K/km

Open this sounding in Storm Lab

The surface observations

Ft Myers/Sw Florida (RSW), 25 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:53 UTC7567190° 15 kt1012.9-RA
23:53 UTC7468190° 11 kt1012.9
00:24 UTC73.468180° 12 kt1012.5
00:39 UTC73.468180° 14 kt191012.5-RA
00:53 UTC7468180° 10 kt1012.9-RA
01:08 UTC64.460.8360° 22 kt321014.6RA BR
01:15 UTC62.659360° 15 kt321014.9+RA BR
01:48 UTC62.659360° 9 kt151015.2RA BR
01:53 UTC6260350° 9 kt1014.9-RA BR
02:01 UTC62.660.8340° 5 kt141015.2-RA

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

The radar

The Tampa radar (KTBW), 136 km away, was scanning. The volume nearest the touchdown began at 00:37 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
00:40 UTCTSTM WND DMGAlvaLee, FLSIX MOBILE HOMES WERE DAMAGED OR DESTROYED NEAR ALVA. TIME IS ESTIMATED OFF OF RADAR.
00:40 UTCTORNADOAlvaLee, FLSIX MOBILE HOMES WERE DAMAGED OR DESTROYED NEAR ALVA. EMERGENCY MANAGEMENT FOUND A NARROW PATH OF DAMAGE. TIME IS ESTIMATED OFF OF RADAR.

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 FloridaEvery tornado in Florida since 1950Warnings in force in Florida nowThe forecast where you are

The other tornadoes of January 25, 2011

6 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
January 254:35 PM ESTEF0Sumter, FL0.930
January 256:15 PM ESTEF0Manatee, FL1.030
January 256:41 PM ESTEF0Hardee, FL0.930
January 257:08 PM ESTEF0Hardee, FL1.130
January 258:09 PM ESTEF0Highlands, FL0.930$5,000
January 2510:50 PM ESTEF0Palm Beach, FL0.250$20,000

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.