EF1 tornado, Logan Martin Res, Alabama, January 19, 2017

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

January 19, 2017

Touchdown

5:58 PM CST (23:58 UTC)

Lifted

6:00 PM CST (00:00 UTC)

On the ground

2 minutes

Path length

0.7 miles (1.1 km)

Path width

175 yards (160 m)

Deaths

0

Injuries

0

County

St. Clair County

Touchdown point

33.478, -86.305

Lift-off point

33.488, -86.302

Record number

1701191758-01

After over a week of near-record to record high temperatures, several upper-level disturbances followed by a strong upper-level low pressure system produced multiple rounds of severe weather across Central Alabama. This system was characterized by strong upper-level winds and very cold upper-level temperatures. The first round produced one brief, weak tornado in St. Clair County on the evening of January 19. The second round occurred on the morning of January 20 with 12 tornadoes across Marengo, Elmore, Macon, Lee, Pike, and Barbour Counties. A third round produced damaging straight line winds on the night of January 21, including in the Birmingham metro area where the Birmingham airport measured a 75 mph wind gust and in Oneonta where 80 mph straight-line winds caused significant damage. A brief tornado also occurred in Tuscaloosa County with this activity. Finally, a fourth round moved through during the day on January 22 with 3 tornadoes across Bullock and Lee Counties.

National Weather Service meteorologists surveyed damage in southern St. Clair County near Treasure Island and determined that the damage was consistent with an EF1 tornado, with maximum sustained winds near 90 mph. A persistent mesocyclone spun up a brief weak tornado within a line of thunderstorms as it passed through St. Clair County. The tornado touched down on Logan Martin Lake just south of the eastern shore of Treasure Island. The tornado tracked northward parallel to and just off the shores of the island, with the initial damage pointing largely offshore. Four boathouses were destroyed and a few trees were snapped or uprooted here, but the path of the tornado was far enough offshore so as not to cause any structural damage to the homes another 50 to 100 feet further inland. As the tornado continued northward across a large cove, it remained completely over water. As it approached the northeastern tip of the island, which jutted out into the lake, the tornado came ashore again and peeled metal roofing off a well-built boathouse. The tornado reached maximum strength here, with 10 large hardwood trees uprooted in a concentrated area in a convergent pattern. The tornado passed offshore again and dissipated before reaching the opposite point on the lake.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

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 Marginal Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:40 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.

Pell City (PLR), 10 km from the path, in the two hours either side.

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

The Birmingham radar (KBMX), 55 km away, was scanning. The volume nearest the touchdown began at 23:54 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 2017 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

1 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.