EF1 tornado, Gass to Hooker, Georgia, April 27, 2011

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.

Rating

EF1

Date

April 27, 2011

Touchdown

8:40 AM EDT (12:40 UTC)

Lifted

8:48 AM EDT (12:48 UTC)

On the ground

8 minutes

Path length

9.9 miles (15.9 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

Property damage

$1.0 million

County

Dade County

Touchdown point

34.859, -85.532

Lift-off point

34.981, -85.442

Record number

1104270640-01

10 damage points were recorded along this path by NWS FFC and NWS HUN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF4. The highest wind the damage implies is 150 mph.

• End point in Alabama of Lakeview to Rainsville to Cartersville EF-5 Tornado.
• End point of Section-Flat Rock, GA EF-4 Tornado in Alabama.
• End point of Bridgeport EF-4 Tornado.

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

A highly diffluent, deep upper trough, centered across Texas, took on a negative tilt and began to rotate northeast during this period. A strong maritime-Pacific (mP) cold front accompanied the upper trough through the mid-south into the southeast from the early morning hours of the 27th to the early morning hours of the 28th. An intense low-level jet with winds in excess of 70 knots was noted in advance of this system and tracked across the mid-south early on the 27th, across north Alabama and north Georgia into the early morning hours of the 28th. West-southwest winds aloft were highly diffluent and near 200 mph across this same region. The strong low-level jet brought unseasonably, warm, moist Gulf air northward in advance of the mP cold front. Dewpoints in the 70s and maximum temperatures in the 80s combined with the extremely strong low-level and upper jets to create an almost perfect environment for severe thunderstorms and large devastating tornadoes. Indeed, the tornado outbreak that affected much of the eastern U.S., but particularly the south central and southeastern U.S. during this period, was unprecedented and likely the largest recorded in U.S. history. The tornado outbreak that accompanied this combination of weather features has been termed the 2011 Super Outbreak, an outbreak even worse than the 1994 and 1974 super tornado outbreaks across the eastern U.S. The outbreak affected the South Central, Southeast, Midwest, and even the usually less tornado prone Northeastern United States. Over 330 tornadoes were reported during this outbreak which began on April 25th and continued into the 28th affecting 21 states from Texas to New York. Even isolated tornadoes were noted in Canada. Nearly 350 people died from these tornadoes, of which over 230 of these were in Alabama alone. Four tornadoes on April 27th in Alabama and Mississippi were ranked EF5, the highest tornado damage rating on the Enhanced Fujita Scale. On average, there is only one EF5 tornado per year in the entire U.S.||Widespread and destructive tornadoes occurred on each day of the outbreak, but April 27th was clearly one of the most prolific and destructive tornado days in U.S. history, probably only surpassed by the Tri-State outbreak of 1925 and the Tupelo-Gainesville outbreak of 1936. The 24-hour period from 8 am April 27th to 8 a.m. April 28th is listed by the National Oceanic and Atmospheric Administration (NOAA) as the fourth deadliest tornado outbreak in U.S. history, with the 24 hours commencing April 28th at 8 a.m. as the fifth deadliest tornado day in U.S. history. It has also been determined to be the costliest tornado outbreaks and one of the costliest natural disasters in the U.S., even after adjustments for inflation, with total damages estimated to exceed $10 billion. ||Georgia was heavily impacted by this tornado outbreak, especially the northwest part of the state which bore the brunt of the massive supercell thunderstorms producing killer tornadoes that tracked east-northeast from northern Alabama during the late evening. All together, there were 15 tornadoes affecting 28 counties within the Peachtree City, Georgia 96-county warning area (CWA) of North and Central Georgia. All of these occurred within a 24-hour period commencing at 8 am April 27th. One of these tornadoes was rated an EF4, the first EF4 tornado in Georgia since the Palm Sunday outbreak in 1994. In addition, there were also four EF3 tornadoes. Fifteen tornado-related deaths were observed in north and central Georgia, the most tornado-related deaths within the Peachtree City, Georgia forecast area since its inception in 1994. The previous highest tornado-related death total was 12 on March 20, 1998, when a tornado struck Gainesville, Georgia.||Finally, it should be noted that while the most significant period of severe weather during this outbreak for Georgia was from the afternoon of the 27th through the early morning hours of the 28th, there was an initial round of severe weather across northwest Georgia early on the 27th as a decaying line of severe thunderstorms moved into the region from northeast Alabama. Widespread wind damage and even a few brief weaker tornadoes accompanied this system into the northwest counties of the state.

A damage survey conducted by the National Weather Service Forecast Office in Peachtree City confirmed that an EF1 tornado had touched down approximately two miles south-southwest of Trenton and tracked north-northeastward nearly nine miles, lifting just before reaching the Tennessee border. This was the first of 15 tornadoes to touch down within the Peachtree City, Georgia forecast area during this historical tornado outbreak across the southern and eastern U.S. The maximum tornado path width was determined to be 100 yards wide with maximum wind gusts estimated to be 100 mph. Only very small portions of the tornado path were rated EF1, namely across Trenton and to the northeast near Lookout Mountain. The rest of the tornado path was rated an EF0. Several homes, mostly in the Trenton area, sustained minor damage as well as an elementary school and bank building on the south side of Trenton along Georgia Highway 136. In addition, dozens of trees were damaged along the path of the tornado.||[04/27-04/28/11: Tornado #1, County #1-1, EF1, Dade, 2011:010].

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

24 minutes of warning. NWS FFC issued a tornado warning for this county at 12:16 UTC, 24 minutes before the tornado touched down, in force until 13:00 UTC.

The county was under a tornado watch, issued at 11:48 UTC and running to 13:56 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 High Risk, with a 0.30 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 06:10 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.

Chattanooga/Lovell (CHA), 29 km from the path, in the two hours either side.

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

The Northeast Alabama radar (KHTX), 54 km away, was scanning. The volume nearest the touchdown began at 12:41 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 GeorgiaEvery tornado in Georgia since 1950Warnings in force in Georgia nowThe forecast where you are

209 more were confirmed in the United States that day.

All 210 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.