When the sirens sounded Wednesday night in Waukesha, most who heard them assumed a tornado warning had been issued. Residents of Muskego and Kenosha heard similar sirens and also assumed that a tornado was threatening.
It turns out the sirens were sounded in those communities (and others) because of the potential for destructive, non-tornado winds.
But wait, you say, they are "tornado sirens." Aren't they supposed to be used for tornadoes only?
I'm told that many local communities reserve the right to sound their sirens for any situation that may be considered a serious threat to public safety. In the case of Wednesday night, the National Weather Service was warning about the potential for winds over 100 miles per hour. Winds of that strength are strong enough to do major to damage to homes, power lines, trees, etc. In my estimation, 100 mph winds do qualify as a serious threat to public safety.
But wait, you say, if the winds are going to be over 100 mph, there has to be a tornado, right?
When certain atmospheric conditions are in place, wind speeds can hit triple digits without the presence of a tornado. We call these "straight-line" winds, as opposed to the rotating winds of a tornado. This type of situation isn't common, but it does happen more often than you might think.
And here's the kicker: What many don't realize is that a large percentage of tornadoes barely get much over 100 mph.
So, in the case of Wednesday night, we had a situation where the potential for damage was about equal to that in most tornado situations. Therefore, officials in many communities determined that the situation was serious enough to sound their warning sirens.
Some communities remained silent. Some may not have deemed the potential for 100-plus mph winds siren-worthy. Others may have a policy that they only hit the horn for official tornado warnings. There may have been other reasons as well.
Whatever the case, there was confusion around why the sirens were going off in some places and not others, as well as why they were going off at all.
The bottom line, I guess, is that when you hear warning sirens, dangerous conditions exist, whether there's a tornado or not.
Craig is a meteorologist who was born and raised in Pewaukee. After getting a degree in Meteorology from the University of Wisconsin-Madison, he worked over 20 years on TV and radio in Milwaukee, Madison, Omaha, Nebraska and Kansas City, Missouri.
Craig spends most of his time trying to keep up with his bride and their three teenage daughters. Any time left over is spent with his other beloveds, the Packers, Brewers and Badgers.