I had not even gotten home from watching last night’s storm when the first critical email about the tornado warning in Sedgwick County hit my inbox. I’d like to spend a moment on the subject of the meteorologist’s dilemma in these situations.
Yes, it was a “false alarm.” A tornado never made it to the ground.
The storm was a “right mover” (tornado indicator), had a hook echo (tornado indicator, image below) and had rotation as measured by Doppler radar (tornado indicator). To the naked eye, there was lots of organized, sustained rotation.
Yet, for reasons meteorologists do not understand, the funnel cloud never made it to the ground. That is good — no tornado damage and no one injured. But, it left people grumping about having to interrupt their activities because of the warning.
In a 2003 paper (available here) I differentiate between “unavoidable” and “unnecessary” false alarms. The former is caused when Mother Nature throws us a curve ball. The latter is when meteorologists know a given area is not threatened but limitations in the warning system cause non-threatened areas to be warned. Last night was some of each.
Take a look at the red polygon which is the National Weather Service’s path-based tornado warning. The hook (funnel cloud) location is within the polygon. The area inside the polygon experienced an “unavoidable” (from my point of view) false alarm because the science of meteorology cannot determine why this situation was not a genuine danger. So, to be safe, we warn.
But, look the radar image again and you see a dot and the word, “Wichita.” That is downtown Wichita where the annual Wichita River Festival was in progress. Because Sedgwick County sounds the sirens countywide, the River Festival and its patrons were subjected to an unnecessary false alarm due to the structure of the county’s siren network. It is “all or nothing.” That put River Festival officials in a no-win situation. They made the right decision (in my opinion) to shelter.
Fortunately, Sedgwick Co. is in the process of changing the configuration of its siren network so that by tornado season 2012 the sirens will only go off in the path of the storm.
The initial tornado warnings last night were absolutely justified given the imperfect state-of-the-art. I’m sure there are plenty of residents of Joplin, Tuscaloosa, Birmingham, Minneapolis, Raleigh, St. Louis, etc., that wish their tornado warnings this year had been false alarms. This is life-and-death business.
That said, I’m empathetic to the people who took shelter for what seems like no good reason. I’m hopeful we will achieve some breakthrough in the science that will allow us to cut down on the unavoidable false alarms.