In a little more than 16 hours, the second-deadliest severe weather day in U.S. history spawned 148 tornadoes that hit 13 states and Canada. Three hundred thirty Americans lost their lives in the storms.
Evidence collected by engineering, construction and weather experts following the storms helped the Weather Service prove that a number of common beliefs about tornadoes were untrue.
"The Weather Service had always held that certain common beliefs about tornadoes were not true, but we didn't have the hard evidence we needed to prove our points," Weather Service Central Region Director Richard P. Augulis said. "Once the damage surveys were complete and pictures and reports were organized, we were able to show just how wrong some of those myths were."
Augulis said some myths disproved
Myth: Tornadoes don't go up and down steep or high hills. Fact: A tornado that hit Guin, Ala., stayed on the ground as it climbed the 1,640-foot Monte Sano Mountain and grew in intensity as it descended the northeast slope. The Blue Ridge tornado of that day formed in the mountains at 1,800 feet just east of Mulberry Gap and crossed a 3,000- foot ridge before moving down to the bottom of the canyon. The tornado finally climbed to the 3,300-foot top of Rich Nob before dissipating.
Myth: Tornadoes will not follow terrain into steep valleys. Fact: The tornado that wiped out three schools in Monticello, Ind., descended a 60-foot bluff over the Tippecanoe River as it moved out of the town and damaged homes at its base.
"Data from the many damage surveys conducted after those storms finally gave us the smoking gun' evidence we needed to prove our assertions," Augulis said. "Being able to show people pictures was much more effective that just talking about what tornadoes are liable to do."
Of equal significance from the damage surveys, Augulis said, was the vast amount of information gathered by engineers who applied what they learned to protecting school children during severe weather. "These tornadoes seemed to target schools, judging by the number destroyed or damaged," Augulis said. "The town of Monticello lost three schools to one tornado and there were 24 schools damaged just in the state of Indiana. Fortunately, the tornadoes started in late afternoon, so the buildings weren't occupied.
"There were a number of engineering studies done on those damaged schools and the information was later incorporated into construction designs to ensure the safety of students. Evidence from the damaged buildings supported the claim that inside hallways provide the safest place and that classrooms with outside walls and gymnasiums with wide roof spans are the most dangerous places for students at school during severe weather.
"As devastating as that
day was, we did learn a lot. We learned about storm movement.
We learned about tornado formation and actions. And we learned
a lot about our agency and how well we were able to function
to keep people safe from harm."