• Check out our interactive map of outdoor emergency sirens in Douglas and Sarpy Counties.
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Sixteen minutes before a deadly twister touched down near Moore, Okla., meteorologists issued a tornado alert, activating a warning system that included outdoor sirens and cellphone alerts.
While Nebraska experiences fewer and typically less-severe tornadoes than Oklahoma and other Tornado Alley states, its warning system is, in some respects, similar.
When a tornado or severe straight-line winds threaten in Douglas and Sarpy Counties, emergency responders activate a network of 182 outdoor warning sirens.
The sirens are the latest evolution of a Cold War-era civil defense system, and the towers are perhaps the most visible symbol of severe-weather preparation.
But the sirens are meant to work for people outdoors, within earshot, so it's wise to prepare in other ways, cautioned Paul Johnson, director of the Douglas County Emergency Management Agency.
Listen for sirens, but also buy a weather radio, he suggested. Sign up for severe weather alerts. Have a storm plan.
If you own a smartphone, check with your wireless company to see if it's capable of receiving automatic emergency alerts. Starting last year, wireless carriers began partnering with government agencies to automatically push out free text messages in the event of severe weather and other emergencies.
And if you do hear a siren, seek shelter indoors, away from glass. If possible, get to a basement or storm cellar. Johnson noted that many people in Oklahoma didn't have basements, a factor that probably contributed to the high casualty count.
Since 1950, at least 20 tornadoes have been documented in Douglas and Sarpy Counties, according to federal weather data. The most severe was an F4 twister that tore through the metro area in 1975, part of a massive storm system that spanned several states. Three people were killed in the Omaha area and dozens were injured.
Since 1986, Douglas or Sarpy has been under a tornado warning 62 times. Each warning was accompanied by a siren blast.
The sirens sound during severe straight-line winds, when the weather service calls a tornado warning or when a funnel cloud sighting has been verified.
Under optimal conditions the sirens are designed to be heard by people outdoors within a one-mile radius. Actual coverage areas vary depending on the placement of buildings and other obstacles, wind speed and a number of other factors. That means most but not all people in the metro area are covered.
“Omaha's not flat, obviously, and it's not an open field,” Johnson said. “We place sirens where we best can.”
A common misconception is that the sirens indicate a worsening situation after a tornado warning has been issued, he said. But a siren is just a different way of issuing the same warning.
The sirens are part of an aging system that requires annual upkeep. Over the winter, water seeps into the casings, corrupting the electronics. Animals build nests in them. Aging components fail.
Any damage is checked and repaired after the sirens are first sounded for testing in February or March, and by the time monthly tests begin, “we've got the system ironed out,” Johnson said.
Sarpy County tests on the first Saturday of the month at 10 a.m., and Douglas County on the first Wednesday at 11 a.m.
Both counties encourage residents to monitor their local sirens for problems.
“Probably some of the best information we get is from the citizens,” Johnson said.
It typically costs Douglas County, which owns most of its sirens, between $12,000 and $17,000 annually to maintain the sirens, Johnson estimated.
In Sarpy County, individual communities and sanitary and improvement districts own the sirens, said Lynn Marshall, Sarpy County's emergency management director.
As the fast-growing county expands, warning sirens — which Marshall estimated can cost upward of $20,000 to install — are one more piece of infrastructure to consider. A new warning siren was installed a few years ago at Werner Park in anticipation of new development in the area, for example.
“It's easier to do it now if the development's moving pretty fast,” he said.
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