The Valley’s “other” tornado season picks up in October

Once the spring and summer months come to an end, it may be easy to think that severe weather season has also ended for the time being.

Or has it?

If you are new to the South, it would be a good idea to familiarize yourself with the phrase "Dixie Alley Tornado Season." This phrase corresponds to the uptick in severe weather that occurs in the fall and winter months in the south.

Alabama Tornadoes by Month

In October alone, as many as 97 tornadoes have touched down in the state of Alabama. This number jumps considerably in November, when 266 tornadoes have touched down between 1950 and 2016.

The Alabama portion of the Tennessee Valley only covers about a quarter of the state, but the tornado trend rings true for the fall months. As many as 23 tornadoes have formed in the region in the month of October, and that number doubles heading into November.

Why the uptick in tornadoes during the fall season?

In the South, the same ingredients that are present for spring season severe weather is present in the fall: A warm, humid (tropical) airmass from the Gulf that is located over the South is violently replaced by cold, dry air surging south from Canada. The interaction of these two airmasses causes strong to severe thunderstorms, some of which have enough rotation within them to produce tornadoes.

In addition, many landfalling tropical depressions, tropical storms and hurricanes spin up tornadoes as they move overland; these landfalling systems often to so during the month of October.

Notable October tornado events

Oct. 24, 1967 Colbert County Damage Assessment (Source: NOAA National Centers for Environmental Information)

October 25, 2010 DeKalb County Damage Assessment (Source: NOAA National Centers for Environmental Information)