More tornado strikes may occur in mobile home parks

It's well-known that one should avoid mobile homes during a tornado, as their relatively flimsy construction and tendency to roll when exposed to high winds leads to numerous deaths each tornado season. The majority of tornado deaths occur in mobile homes for this reason, but tornado experts have long wondered why mobile home parks seem to get disproportionately more tornado strikes than other residential areas. New research by Purdue University researchers Olivia Kellner and Dev Niyogi suggests that "transitions zones"--areas where dramatically different landscapes meet, like where a city fades into farmland, or a forest meets a plain--are more prone to tornado touch downs. Since mobile home parks are often located at the edge of built-up areas, they may actually get hit more often.
Figure 1. Damage to 2-year-old C.J. Martin's mobile home park near Evansville, Indiana due to a November 6, 2005 tornado. Twenty people. including C.J., died in the F3 tornado that devastated his Eastbrook Mobile Home Park in Evansville. The storm hit at 2am, when many residents were asleep and didn't hear the tornado sirens. C.J.'s mother, Kathryn Martin, pushed lawmakers to adopt a bill requiring all mobile homes in Indiana to have a weather radio with a tone alert system, which could have saved many lives in the mobile home park that night. C.J.'s Law was signed into law by Indiana governor Mitch Daniels later that year. Image credit: Paducah, KY NWS.The researchers studied where tornadoes touched down in Indiana between 1950 and 2012, and found that 61% of tornado touchdowns occurred within 1 kilometer (about 0.62 mile) of urban areas, and 43% fell within 1 kilometer of forest. Kellner said the percentages suggest that certain locations may increase the likelihood of tornado touchdowns due to increased "surface roughness"--an abrupt change in the height of land surface features, which can stretch or squash a column of air, increasing its rate of spin, which could contribute to the formation of tornadoes. 
Forecasters and city planners may need to pay closer attention to these "transition zones" to better understand tornado risks, said Olivia Kellner, doctoral student in the Department of Earth, Atmospheric and Planetary Sciences in a press release."
There are still many unanswered questions about tornado climatology, but what we're finding  is that  there may be a relationship between the Earth's surface and the atmosphere that      contributes to  where tornadoes tend to touch down." The study also found that tornado touchdowns in urban areas tend to occur at about 1 and 10 miles from the city center. Kellner said these "rings" of   increased tornado activity could be related to how cities are developed. "Cities impact the surrounding climate in terms of regional airflow and temperature," she said. "The size of cities, what they're made of and the heat they produce are factors that could affect the microclimate." 
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