It is now known as the predominant tornadic signature on radar, but it didn't use to be. When radar first came online for airplane purposes, it was really unknown just how effective it would be at capturing meaningful thunderstorm activity. But on this date 61 years ago, all of that changed when the first documented hook echo was captured as a tornado pushed northeast in Illinois. This was a major milestone for weather prediction and ultimately shaped the future of our understanding of how thunderstorms work. The story now from the state climatologist office in Illinois:
The Illinois State Water Survey is home to the first ever documented radar hook associated with an actual tornado. Water Survey staff captured the historic event on film on April 9, 1953. This was a major turning point in monitoring severe weather, demonstrating that tornadoes could be identified by radar. This discovery helped lead to the first national weather radar network in the United States.
The radar was located at Willard Airport, south of Champaign IL, and was being used along with a rain gauge network to relate radar signals with rain rates. Don Staggs, the radar technician, had stayed late to complete repairs on the radar. While testing the repairs, he noticed an interesting radar return and began recording the radar scope using the mounted 35 mm camera. As a result, he captured a well-defined hook echo (see photo) on film. Afterwords, researchers related this information to damage and photos along the tornado's path.