62 years ago this month, April 9, 1953, about 3 miles from where I am sitting, a tornado was caught by radar for the first time. Scientists and electrical engineers at the Illinois State Water Survey at the University of Illinois at Urbana-Champaign had modified a former WWII airborne radar for use in estimating amounts of precipitation falling from storms.
Don Staggs, an electrical engineer, was preparing the radar for later field tests. He started to notice what we now call “hook echo” returns in the scans of the storm. As afternoon turned to evening, a strong thunderstorm developed just north of Champaign, about ten miles from the radar site at the university-owned Willard Airport. The storm image included a pronounced hook on the bottom rear flank much as we see hook echoes on modern Doppler radar.
Still photos and a 16mm film of the images on the scope captured that moment. A team of meteorologists and technicians were able to study the image capture. Later, Dr. Ted Fujita the creator of the tornado strength measurement scale that bears his name, sketched over 200 of the frames of the film in his own hand. All of this can be seen in a terrific article from Colorado State University. Note especially the photos of the tornado and the well-developed wall cloud.
We now know that the radar captured the early stages of an F3 tornado that eventually traveled about 160 miles and dissipated near Albany, IN. There were two fatalities and about $4-million in property damage in Illinois. The path of the storm took it across mostly rural areas.
Next week, we’ll discuss current use of radar and what may be the next generation of this important forecast tool.