How tornado sirens operate in Michigan, and other ways to stay on alert

• A tornado struck Livonia Wednesday afternoon but wasn’t detected on the National Weather Service’s radar 
• The NWS said the storm formed too quickly to alert city officials, which is why the city’s tornado siren wasn’t activated
• Each locality operates and manages its own outdoor tornado sirens. Some of them are activated by NWS tornado alerts.

An unforeseen tornado struck Livonia Wednesday afternoon, so quickly that the National Weather Service didn’t have time to alert city officials to sound outdoor alarms warning people of the incoming storm.

The National Weather Service called it a  “spin-up storm” as it formed so rapidly that weather radar had not picked it up. 

The tornado snapped tree limbs and uprooted trees including one that fell through the roof of a Livonia home, killing a toddler and severely injuring a woman, who were both sleeping. 

“With the number of severe events we've had so far, just managing a tornado potential can be tricky,” said Brian Cromwell, meteorologist for the National Weather Service’s Detroit office. “There was nothing ahead of time that would have suggested tornado formation. There was a very weak signature on the radar when it did pop up.” 

Related:

• Michigan tornadoes: By the numbers
• Cleanup begins from SW Michigan tornadoes: ‘We found homes in the roadway’
• Michigan to monitor smog in eight counties amid switch to summer gasoline

To better understand how sirens are operated across the state, Bridge Michigan spoke to the head of the state’s Emergency Management and Homeland Security department and a storm chaser. 

Who is responsible for activating a siren when there is a tornado warning? How are they activated?

“Those outdoor warning sirens are installed, maintained by the local county or city jurisdictions,” said Kevin Sweeney, deputy state director for the Department of Emergency Management and Homeland Security. “They’d be activated by the local public safety, so whether it's police, fire, emergency management, or potentially could also be the 911 Center.”

Sirens can be activated in various ways depending on the jurisdiction. There is no state mandate requiring local governments to have outdoor tornado sirens, Sweeney said. The cities that do have them are responsible for testing and operating them.

Localities can program their sirens to automatically activate after the National Weather Service issues a tornado alert.  Other cities may opt to manually activate the siren once they receive the alert. Livonia activates warning sirens “based on notifications from the National Weather Service, public safety officials or NWS-trained weather spotters,” the city said in a statement Wednesday.

How often are tornado sirens tested?

Each city or township can choose when and how often the sirens are tested. In many areas across the state, it is common for the sirens to be tested monthly. However, in Oakland,  Kent and Hillsdale counties, those tests are suspended during the winter months. 

The state also hosts an annual statewide tornado drill where local agencies can voluntarily sound the siren, which gives residents the opportunity to prepare for a real tornado. 

How many sirens are there across the state? Does every city or county have one?

A city can have several outdoor sirens or none at all. 

“The sirens are used to notify people that are outside,” Sweeney said. “They're not designed necessarily to reach somebody that's inside a building or a house or a church or something like that.” 

Because the siren may not be heard from indoors, people are discouraged from relying solely on sirens to be alerted when there is a tornado. 

“There's no one set criteria to sound sirens, so it's often unreliable, and a lot of people can't hear them indoors,” said Ryan Harriott, president of Michigan Storm Chasers, an organization of individuals who chase storms and provide forecasts and weather information to the public.

Other ways Harriott recommends people prepare for tornadoes are to program their phones to receive severe weather alerts, buy a NOAA weather radio from a local retailer , pay close attention to weather apps and social media, watch forecasts on television and stay connected with family and friends.  

What does a tornado siren sound like and how do people know that’s what it is?

“Typically, it's a very high-pitched whine,” Harriott said. “There are some sirens that are lower pitch, but those are pretty rare.” 

Some cities may sound the outdoor siren multiple times and others just once before a tornado. 

“Typically they sound consecutively for about two or three minutes, and they’ll shut off and that's how you know it's a siren,” he said. 

What is a ‘tornado emergency’ and how is that different from a tornado warning?

The National Weather Service issued the state’s first tornado emergency last month when several tornadoes swept through southwest Michigan, prompting Gov. Gretchen Whitmer to declare a state of emergency in Kalamazoo, St. Joseph, Branch and Cass Counties. 

A tornado warning is issued when a tornado has been indicated by a weather radar or spotted in a specific area. People in these areas should take cover on the lowest floor of a building and avoid windows.

A tornado emergency is the service’s highest alert level and is issued when a violent storm has reached an area. These alerts are issued when there is a severe threat to human life or property and devastating damage is confirmed.

More on Wednesday’s storms

The NWS categorized the storm that hit Livonia as an EF-1, which reached winds up to 95 mph at its peak. The tornado touched down just east of Schoolcraft and Eckles Road at 3:30 p.m. and traveled 5.5 miles northeast. It lifted at 3:39 p.m. southwest of Seven Mile and Middlebelt Road. 

The most affected neighborhoods are those near Interstate 96 and Newburgh Road. 

A second tornado swept through Crawford County, Wednesday afternoon, the National Weather Service confirmed. The EF-0 storm reached 80 mph at its peak and lasted about a minute.