By JEFF MARTINATLANTA (AP) â¿¿ Photos and mementoes that were snatched up and blown hundreds of miles during a Southern tornado outbreak two years ago are giving researchers new insight on how debris is carried by the storms and how it could threaten the public. A new study has documented how one photo traveled nearly 220 miles over Alabama and Tennessee, said John Knox, an associate professor of geography at the University of Georgia who led the research. That is among the longest-documented trajectories of tornado debris. The slightly scratched snapshot, which shows a stream flowing through a mountainous landscape, traveled from the northwest Alabama town of Phil Campbell to the east Tennessee town of Lenoir City. The study was recently published online by the Bulletin of the American Meteorological Society. It tracked the direction the items traveled in relation to the storms that struck Alabama and other Southern states on April 27, 2011. The researchers analyzed the takeoff and landing points of the items using geography software and mathematical models. Most debris fell slightly to the left of the storm's track. But the items that traveled the farthest were found to the right of the path. Knowing where the debris is likely to fall could help protect the public if a tornado were to strike a hazardous site and suck up toxic biological or radioactive debris, Knox said. "We need to get enough understanding so we can get fairly reasonable predictions of where the stuff goes," said John Snow, a professor of meteorology and dean emeritus at the University of Oklahoma who studied tornado debris in the 1990s. Knox's study builds on research done by Snow and others. Though nuclear reactors are designed to withstand the force of tornadoes, radioactive materials such as fuel rods are often stored nearby, Snow said. A direct hit on such material is one of many catastrophic scenarios involving tornado-blown debris.