Study: Winter tornadoes to get more powerful as world warms

Nasty winter tornadoes -- like the deadly ones last week that hit five states -- are likely to be stronger and stay on the ground longer with a wider swath of destruction in a warming world, a new study shows.

The combination of a longer and wider track with slightly stronger winds means some rare winter tornadoes that are killers now will have nine times more the power by the end of the century if carbon dioxide levels continued to rise, according to a study presented at the American Geophysical Union conference Monday.

The study, which pre-dates the devastating Mayfield, Kentucky, tornado outbreak, looks at strength and not frequency of big tornadoes as climate change progresses. Not peer reviewed yet, it was presented in poster form as a peak at new research to be published later.

"There is a potential for events in the future that are more intense that would not have been as intense in the current climate," said study author Jeff Trapp, head of atmospheric sciences at the University of Illinois, Urbana-Champaign. "Bearing in mind that these high end events are still going to be rare."

Trapp took the conditions during two large tornado strikes in 2013 -- the Hattiesburg, Mississippi, tornado that in February of that year injured 82 people with winds of 170 mph and the Moore, Oklahoma, tornado that killed 24 people with winds up to 210 mph (340 kph) in May-- and put them into dozens of computer simulations of worst-case climate change scenario by 2100, which other scientists say is increasingly unlikely.