National Weather Service United States Department of Commerce


Treasure Island EF-1 Tornado (St. Clair County)
  January 19, 2017


Event Summary

National Weather Service meteorologists surveyed damage in southern St. Clair County near Treasure Island and determined that the damage was consistent with an EF-1 tornado. 

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.  The tornado was .7 miles long and was 175 yards wide at its widest point. The tornado  was rated an EF-1 with maximum winds around 90 mph. 

Thanks to the St. Clair County EMA for their assistance with this survey.







Estimated Maximum Wind:
90 mph
Damage Path Length:
0.7 miles
Maximum Path Width:
175 yards
Approximate Start Point/Time:
2 ENE Coosa Island 33.4785/-86.3045
at 558 pm CST
Approximate End Point/Time:
5 SSW Pell City
at 600 pm CST


GIS Data



Reflectivity (left) and Velocity (right) at the time of the tornado.
Images are from KBMX at 600 pm CST.


  Boathouse damage

Boathouse damage