Purdue Study Examines Where Tornadoes Strike
April 8, 2014 – Landscape “transition zones” may be more likely than other areas to be struck by tornadoes. The finding is part of a Purdue University study from the school’s Department of Earth, Atmospheric and Planetary Sciences. Areas where landscape shifts, such as from urban to rural, or forest to farmland, may have a higher likelihood of severe weather.
The study, authored by Purdue University doctoral student Olivia Kellner and Dev Niyogi, Indiana’s state climatologist, analyzed locations where tornadoes touched down between 1950 and 2012 based on records from the National Weather Service’s Storm Prediction Center. The data showed that 61 percent of tornado touchdowns occurred within 1 kilometer (about 0.62 mile) of urban areas while 43 percent of touchdowns fell within 1 kilometer of forest.
A possible explanation for the correlation is increased “surface roughness” – an abrupt change in the height of land surface features – which can change the shape of a column of air, increasing the air’s rate of spin and contributing to the formation of severe storms.
“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,” Kellner said.
Co – author Niyogi says identifying areas of high risk could eventually lead to changes in the way cities are designed which could reduce the conditions associated with producing severe weather. “As we continue to modify our landscapes, there will be many environmental and societal changes,” he said. “But perhaps we have the potential to engineer cities to be more resilient to severe weather by thinking holistically about the way cities can be developed and how they affect local climate conditions.”