With severe weather upon us, it’s time to brush up on sirens

CEDAR RAPIDS — To prepare for an emergency, outdoor sirens in the Corridor continually are tested and updated. But Dave Wilson wants to remind you of their purpose.

'A lot of times we get calls that say, 'Hey, we didn't hear the siren.' 'Where were you?' 'I was in my house.' 'Well, it's not designed to be heard inside your house. It is an outdoor warning siren designed to make you go inside to learn more information,' said Wilson, the Johnson County Emergency Management coordinator.

May, June and July are historically the worst for tornadoes in Iowa, according to the National Weather Service. Last year, 26 of the 58 tornadoes reported in the state took place in those three months.

Outdoor sirens were first installed in the Cold War era to alert of military attacks. It wasn't until later they began warning of bad weather.

Johnson County has 62 outdoor warning sirens, and the emergency management team owns and oversees 11 of those in rural areas.

Linn County has almost 140 sirens, with 109 of those owned by the NextEra Duane Arnold Energy Center. The nuclear plant is federally required to provide a 10-mile siren coverage area from its location in Palo. Linn has six sirens in rural areas, and the remaining ones are managed by municipalities.

On the first Wednesday of every month, Linn's are tested at 8:45 a.m. and Johnson's at 10 a.m.

For real weather emergencies, sirens are activated by city or county officials, police or fire department or other emergency management personnel when a circumstance meets National Weather Service guidelines. Linn and Johnson counties follow the same criteria:

• A tornado warning is issued by the weather service.

• A funnel cloud is reported by a trained spotter.

• A severe thunderstorm warning is issued by the weather service, or reported from a trained spotter.

• Golf-ball size or larger hail is spotted.

• Wind gusts to 70 mph or greater.

Since there are no federal or state regulations for the sirens, the sites selected for them, the choice of equipment and the schedule of maintenance and upgrades fall to city and county officials.

Coralville installed its seventh siren Friday at the corner of Jones Boulevard and Liberty Drive, near the intersection of interstates 80 and 380.

'There is quite a bit of growth over in that Jones Boulevard area, and the other things we consider is wind direction from a major storm usually comes in from the west, and that helps blow the sound in a certain direction,' Coralville Fire Department Chief Dave Stannard said,

Iowa tornadoes since 1950 and current siren coverage areas

Linn and Johnson County siren coverage circles indicate the estimated outdoor effective range of the sirens. Atmospheric conditions and topography may affect siren range. Lines represent beginning and end points for tornadoes, when that data was available. Data from National Weather Service, Linn County Emergency Management Agency and Johnson County Emergency Management Agency. Map by John McGlothlen / The Gazette

Wilson said the sirens can have a coverage area from 1 to 3 miles, but environmental factors like wind, hills, buildings and even leaves on the trees hamper the range.

'An area that might be covered today by a siren might not be covered as well tomorrow — they are very flaky,' Wilson said, although he did compliment their effectiveness for parks or other high-density areas.

'It is a love-hate relationship you will find with a lot of emergency managers with outdoor sirens. They are affected by so many different variables,' he said.

Each siren, including installation, can cost upward of $25,000. Stannard said solar powered sirens saved Coralville $9,000 in electric costs over the 12 years the three solar powered sirens there have operated.

Duane Arnold Energy Center in Palo has 144 sirens in the 10-mile area and 109 are in Linn County. The others are in Benton County.

The energy plant allows the counties to use the sirens for weather notifications.

According to the plant's communications specialist, Megan Murphy Salyer, it invested about $4 million in 2012 to upgrade its outdoor warning systems in Benton and Linn. The upgrades include replacement of sirens, installation of solar panels and upgrades in the backup battery system. She said the upgrades to all of the sirens will be completed by 2019.

The emergency management agencies — not the plant — are responsible for alerting the public over the sirens during weather emergencies, she said.

High wind warnings are what people in the Corridor most need to pay attention to, both emergency management agencies said.

Johnson County was the 'poster child' to start the high-wind activation policy after Jennifer Lewis, a Kennedy High School teacher, died after a tree blew onto her tent at Lake Macbride State Park in May 2011, Wilson said.

Then in June 2014, a 57-year-old Cedar Rapids man was found dead after emergency crews responded to reports that a building was blown down by high winds in a Fairfax storm.

Still, rural and wooded areas may be better served from alerts in your pocket, Wilson said.

'I think 20 years from now (sirens) will be pretty antiquated technology. In this day and age, everyone is on the go, and have mobile devices on their hips we have really seen a huge shift,' Wilson said. 'It is becoming more and more a backup system, and not a primary system.'

All but 10 Iowa counties have signed on to use the Alert Iowa mobile system. Alert Iowa is a mass notification and emergency messaging system that can be used by state and local authorities to send emergency information to the public.

The system is free to use. To sign up for the mobile alerts, go to the Linn or Johnson county emergency management websites.