The experimental project was used last year by National Weather Service offices in Missouri and Kansas to improve communication during tornado warnings. Residents in Greene, Macoupin, Pike and Calhoun Counties were first to see the warnings in Illinois.
Chris Miller, meteorologist at the Lincoln National Weather Service, says starting April 1st the impact-based warning system will be used throughout the Midwest and Great Lakes, including West Central Illinois.
“There was an independent review by emergency management officials of this experiment and it was recommended that the experiment expand to all of the Midwest, look at it further, study it more and get more feedback from our partners and the public," says Miller.
Words like “mass devastation,” “unsurvivable,” and “catastrophic” will be part of tornado warnings based on the severity of a storm’s expected impact. Miller says the goal is to more successfully communicate the danger of an approaching storm.
“In the past, the tornado warnings that we've issued were kind of a one-size-fits-all," says Miller. "We know that tornadoes are all different, but anytime we had a tornado that even had a brief touchdown, all the way up to an enormous tornado that could cause mass destruction or injuries and fatalities, we used the same warning. So, what we've decided to do with this experiment was expand that."
There will be three levels to tornado warnings. If Doppler Radar detects a rotating thunderstorm the tornado warnings will be “radar indicated”. If a tornado is spotted by the public the warning will say “a tornado is on the ground.” These two descriptions have been used for several years.
The two new descriptions will say a tornado on the ground will cause “considerable damage” or a tornado on the ground will cause “catastrophic damage”. These phrases will be used when radar, weather spotters, and law enforcement have confirmed a large tornado.
“But that is going to be extremely rare," says Miller. "That would be for like a once-in-a-lifetime type of tornado, so if anyone did hear that the point that we're trying to get across is this storm really mean business. It's big, it has a lot of potential to produce damage and possible injuries and fatalities. We want people to pay attention to that."
The impact-based warning system began to better communicate storm threats after 158 people were killed when a tornado ripped through Joplin, Missouri in 2011.