Tulsa sirens for tornado warnings said better than not at all
BY MICHAEL OVERALL World Staff Writer
Tuesday, April 03, 2012
4/03/12 at 7:59 AM
One stormy night last April, as an ominous rotation moved along the Interstate 44 corridor, tornado sirens went off four separate times in Tulsa.
When it was all over, some tree limbs had broken and a few thousand homes went briefly without power. Other parts of the state saw tornadoes, but not Tulsa.
A false alarm?
"By no means," says Roger Jolliff, director of the Tulsa Area Emergency Management Agency.
"The conditions were right for a tornado to drop at any minute. If we wait to see if there's going to be any damage, it's too late to warn people."
In Oklahoma, local officials must decide for themselves if, or when, to use tornado sirens.
But they generally follow advice from the National Weather Service. If forecasters issue a tornado warning, the sirens will almost certainly be activated.
In 76 percent of tornado warnings, however, a tornado never materializes, according to records from the Weather Service.
And that makes Jolliff worry about crying wolf.
"The last thing we want to do is overuse the system," he says, "because we want people to react when we do warn them."
In Joplin last year, the sirens sounded 23 minutes before the catastrophic F-5 tornado hit the ground at 5:34 p.m. May 22.
People didn't exactly ignore the warning, but they didn't run for cover either, according to a survey conducted by the Weather Service.
Having heard the sirens many, many times before, "the vast majority of Joplin residents" had grown complacent, the report says.
Instead of taking shelter right away, some went to look outside. Others turned on a TV, listened to a radio or checked online.
In other words, they waited for "additional credible confirmation" because they didn't believe the sirens, according to the report.
It's supposed to work the other way around, of course.
"People should begin their storm precautions by monitoring the media," Jolliff says. "When you hear the sirens, that's your last warning. It means you are in danger now."
He often struggles with the decision to trigger the sirens, and his staff might stay on the phone for hours to receive constant updates from storm spotters and forecasters.
But ultimately, it comes down to a simple question.
Would you rather sound the alarm and nothing happen? Or not sound the alarm and have a tornado after all?
"We will err on the side of caution," Jolliff says. "When you hear the sirens, it means we have weighed the consequences of warning or not warning, and we have decided that the public needs to be warned."
In its assessment of Joplin's reaction to storm warnings, the Weather Service recommends developing a "tiered" system of alerts that would convey the level of risk.
Early warnings would seem relatively routine, putting the public on notice that a more urgent alarm might come later.
As the risk increases, the warnings would ratchet up, with the most severe alarms reserved for rare occasions.
Starting this week, the Weather Service will take a step toward such a system in Missouri, where storm warnings will include "scare words" to describe the level of expected destruction.
Some storms, for example, will threaten "mass devastation," while others might be "catastrophic" or even "unsurvivable."
The descriptive storm warnings might expand nationwide next year.
But weather bulletins go out to broadcasters, newspapers and emergency management officials - not to the general public. The average person might not notice much difference.
And presumably, the new warnings won't change how often the tornado sirens are used.
Nonetheless, Tulsa should take the sirens seriously, Jolliff says.
"We're not using them lightly," he promises.
Jolliff's agency controls 87 sirens. But combined with other towns, the county has more than 200 sirens that blanket more than 90 percent of the population.
Still, about 58,000 county residents live out of earshot of the sirens, according to recent estimates from emergency management officials.
Forecasters expect scattered thunderstorms in the Tulsa area Tuesday.
Warning flags
Average warning time before a tornado: 12.5 minutes.
Average warning before an F-5 tornado: 17.8 minutes.
Tornadoes that hit with no warning: 30 percent.
"False alarms" from tornado warnings: 76 percent.
Source: National Weather Service.
Words for storm warnings expected to intensify
Covering Missouri and at least parts of Kansas, the new "impact-based" storm warnings will use stark language to describe severe weather.
Possible warnings include:
"Mass devastation is highly likely, making the area unrecognizable to survivors."
"Complete destruction of entire neighborhoods is likely."
"This storm is not survivable."
"This is an extremely dangerous tornado with complete devastation likely."
"Mobile homes and outbuildings will offer no shelter from this tornado."
Original Print Headline: Sirens' use in tornado season is defended
Michael Overall 918-581-8383
michael.overall@tulsaworld.com
