'Second' tornado season in U.S. brings near record October numbers
Once all the reports are tabulated, October 2021 could place as the second-highest for tornadoes during the month, just behind 2018 (123). The high sum includes five individual outbreaks, with tornadoes observed on 14 days of the month.
October was an active month for tornadoes in the United States, almost tying a record and bucking a trend in what has been a below average year for twisters in the country.
The National Weather Service's (NWS) Storm Prediction Center's preliminary October tornado tally is 119, about twice the long-term average for the month.
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Once all the reports are tabulated, October 2021 could place as the second-highest for tornadoes during the month, just behind 2018 (123). The high sum includes five individual outbreaks, with tornadoes observed on 14 days of the month.
"There was plenty of warm air east of the Rockies. This means a little more energy, and also a sign we had a stronger flow off the Gulf of Mexico, which means a little more moisture and a stronger front for those systems that move across," says Kevin MacKay, a meteorologist at The Weather Network.
Another particular highlight was that Oklahoma, in the heart of Tornado Alley, more than doubled its October twister sum in 2021. Prior to the month, the state had only recorded 25 tornadoes for the year.
Once October came around, it saw 31 twisters in four days through the course of the month -- more than twice the previous 2021 tally and pushing Oklahoma closer to its yearly average.
Besides Oklahoma being at the hub of the activity, tornadoes were recorded sweeping across the northern Gulf Coast and Missouri, reaching as far north as North Dakota and Pennsylvania, according to the Washington Post.
Several of the twisters were considered strong or intense, garnering EF-2 or EF-3 ratings on the Enhanced Fujita (EF) damage scale.
As well, an outbreak of 19 tornadoes occurred near the Ohio and Pennsylvania border on Oct. 22 -- an event that would be abnormal at any time of the year (let alone in October). Because of that, the NWS Cleveland branch issued the greatest number of tornado warnings it had put out in a single day since 2005.
It wasn't the only noteworthy October outbreak, with another event occurring in Missouri on Oct. 24, with two tornadoes rated EF-3.
A tornado that hit Mississippi on Oct. 27 killed one person, its first October tornado fatality in seven years. Despite the near record-high tornadoes for October, the death was the only one recorded across the country during the month.
OCTOBER IS THE 'SECOND' TORNADO SEASON
The jump in tornado activity occurred during a time that is not normally conducive to the formation of powerful thunderstorms, making for an odd statistic among a year with less twisters than usual.
As the sun’s warmth gradually winds down through the fall, this means there is less available environmental energy, leading to limited opportunities for twisters to form. As a result, the drop in favourable conditions typically means a plummet in tornado counts, normally lower than during the spring months.
Despite this, October can be thought of informally as a “second season” for severe weather, including outbreaks, but are typically limited in reach.
Similar to what occurs during the spring, the jet stream can serve as an agitator for severe weather to develop. As it dives back down to the Deep South after a stay in the North during the summer, its powerful winds foster atmospheric spin, which can ignite tornadoes when the other factors are present.
Orange, Texas. (Mary Phan via Storyful)
Although the sun’s energy in October is considerably less potent than it is in the spring, when warm, humid air from the Gulf of Mexico is sent north and links with an intense fall jet stream, this can spell trouble as a barrage of tornadoes can occur.
Thumbnail courtesy of Mary Phan via Storyful, taken in Orange, Texas on Oct. 27 2021.
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