For the second consecutive year – and the fifth time since the turn of the century – the number of sizable tornadoes that touched down around the United States in 2013 was far below normal, weather officials said.
Kansas bucked the trend, with a near-normal total, but weather officials say most of the 58 tornadoes that touched down in the Sunflower State were weak and short-lived.
National tornado totals were flirting with a record low until outbreaks on Oct. 31 and Nov. 17 added “substantially” to the total, said Greg Carbin, warning coordination meteorologist with the National Oceanic and Atmospheric Administration’s Storm Prediction Center.
Only 388 tornadoes rated EF-1 or higher had touched down in the U.S. by the end of November, Carbin said. That number will rise following a series of tornadoes in the South the weekend before Christmas, but the total through November is the 10th-lowest number since official records began being kept 60 years ago.
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The record for fewest EF-1 or stronger tornadoes over the same period is 283, set in 2002. The average number of tornadoes in the country is about 1,200.
“We’re in a particularly quiet period for overall tornado activity on an annual basis,” Carbin said in an e-mail response to questions.
There were only 333 tornadoes rated EF-1 or higher through the first 11 months last year and 394 in 2006. While the total number of tornadoes reported has grown dramatically in the past 10 years compared to decades past, almost all of the growth has occurred in the number of weak tornadoes rated EF-0, with winds of less than 85 mph.
Weather officials credit that increase to the fact that few tornadoes, even weak ones, go unnoticed due to the prevalence of storm chasers and spotter networks.
The last time officials noticed a distinct downturn in tornado numbers – the mid- to late 1980s – speculation blossomed that Tornado Alley was dying.
No one is suggesting that now. Not with 2011 still fresh in the memory.
That year saw 1,691 tornadoes reported across the country, more than any other year on record except for 2004. Numerous tornado records were broken in 2011, including the most tornadoes in a single day and a single month.
The two years since then haven’t seen that many tornadoes combined. The 2012 season was stifled by a dome of high pressure that settled over the eastern two-thirds of the nation in mid-April and didn’t budge until the year was virtually over.
This year’s tornado drought was caused by something else entirely, said Larry Ruthi, meteorologist-in-charge of the National Weather Service branch in Dodge City.
“The environment” conducive to tornadoes “was a much shorter time period than in a typical year,” he said. “It was very active that two- or three-week period” in late May and early June.
But other than that, he said, it was very quiet for tornadoes. Early spring was cold – Wichita nearly set a record for latest measurable snowfall in early May – and the atmosphere was too stable to favor the development of strong thunderstorms.
“The storm track was weak and generally to our east,” said AccuWeather senior vice president Mike Smith, who calls Wichita home.
The jet stream pushed north of Kansas by late June, stabilizing the atmosphere in a different way by limiting air flow in the upper atmosphere.
Even with its low numbers, however, 2013 had its share of large, devastating tornadoes.
The deadliest of them all was the mile-wide EF-5 tornado that killed 24 people in the Oklahoma City metropolitan area on May 20. What became known as the Moore tornado was on the ground for about 14 miles and about 40 minutes.
Less than two weeks later, another large tornado killed eight people in the same metropolitan area – including three veteran severe-weather researchers. The El Reno tornado was ultimately rated an EF-3 and at one point was 2.6 miles wide – the widest tornado on record. The tornado traveled 16 miles and was on the ground for 40 minutes.
“People’s perceptions of tornado seasons are highly influenced by what occurred nearby,” Smith said. “It would be hard to convince people in the Oklahoma City area that 2013 was a ‘below normal’ season.”
Kansans would likely feel the same way, though a couple of near misses by large tornadoes spared the state of potentially substantial deaths and injuries.
On May 18, an EF-4 tornado passed within a mile of the small Pawnee County town of Rozel. The wedge-shaped tornado was wider than the entire town, meaning a direct hit would have decimated the community.
“It would have been another Greensburg,” one resident said, referring to the Kiowa County town devastated by a massive tornado in 2007.
Just a day later, a tornado touched down near Clearwater and moved northeast toward Wichita before lifting just outside the city. It was given an EF-2 rating, though Smith said in a blog post about the storm that circulation in radar wind data was so intense it resembled the deadly EF-5 tornadoes that struck Greensburg in 2007 and Joplin, Mo., in 2011.
“Say some prayers of thanksgiving,” Smith wrote at the end of his blog post about the tornado. “This could have been another Joplin in terms of the damage the storm could have done.”
There were 15 tornadoes confirmed in the 26 counties of southeast Kansas included in the warning area covered by the Wichita branch of the National Weather Service. The May 19 tornado was the strongest of them all.