After emerging from the snow and cold of winter, severe weather season starts up in Michigan.
The outdoor warning sirens, which sound for tornadoes and–in some communities–for particularly strong severe thunderstorms, may motivate you to take shelter. Most severe storms will never prompt a siren, and a normal or baseline severe thunderstorm warning may not elicit the same urgency. This is a mistake that puts people in jeopardy.
At what point does a thunderstorm become severe?
A severe thunderstorm warning is issued when an imminent storm is capable of producing winds of at least 58 mph and/or hail of at least the size of a quarter, or one-inch in diameter.
That is the baseline for the warning, but hail can be bigger and winds can be higher.
A storm on July 26, 2023 was a prime example of why it is important to treat severe thunderstorm warnings like tornado warnings. On that summer afternoon, a line of powerful thunderstorms swept across Southeast Michigan. The Ann Arbor and Detroit areas, including Redford Township, were hit hard.
Rosemary Bessette, of Redford, witnessed the storm’s intensity and aftermath.
“The rain was coming hard; and then, the wind just kicked in and everything was going pretty much horizontal. It was going sideways. I saw branches. Furniture,” she said.
Bessette said her wife suffered flash burns from arcing power lines by their home. Their property was surrounded by downed trees and branches.
“They took out both of our vehicles. We’ve got damage to both of our vehicles, and it looks pretty extensive. And it was just unreal.”
Following the straight-line thunderstorm winds of up to 80 mph, the damage was comparable to what you might observe from a weak tornado.
The winds left their mark across the township, including Dan Haas’ front yard. One of the tree limbs landed on his car.
“I think it hit right here and (sent) shock damage throughout the whole rear window,” he explained.
The damage was a shock for Marcullus Head, who was about to move himself and his family into their new home the next day.
“Plan for tomorrow was to move. I can’t do it now. No power. Trees are down.”
The storms of July 26, 2023 resulted in no serious injuries, but some storms permanently scar.
Tornado Outbreak of 1997
On July 2, 1997, a total of 13 tornadoes touched down in Southeast Michigan, which is the most ever for a single day in the region. Tragically, the tornadoes killed two people and injured about 100 others. The straight-line winds added to the casualties.
In Grosse Pointe Farms by Lake St. Clair, a family had sought shelter from the approaching storm in a gazebo when 100-mph winds blew it into the lake. Five people drowned and eight were hurt.
Southern Great Lakes Derecho of 1998
The next spring, May 31, 1998, a derecho raced across the state with winds of 60 to 90 mph. [A derecho is a large line of severe thunderstorms, which travels over hundreds of miles.] Some West Michigan communities saw damage consistent with winds of up to 130 mph, which is equivalent to the strength of an EF2 tornado. In Lower Michigan, four people died and 140 were hurt. More than 12,000 homes and 800 businesses were damaged, including in Metro Detroit, according to the National Weather Service. More than 800,000 customers lost power statewide.
Most thunderstorms never become strong, but numerous storms have caused damage in the area over the years.
In addition to being capable of dangerously high winds and large hail, thunderstorms produce lightning and occasional flooding. In some instances, severe thunderstorms can also spin up tornadoes with little to no warning.
Due to the risks, it is important to get indoors, away from windows, and on the lowest level for severe thunderstorms. Have a plan, practice the plan, and take shelter anytime threatening weather approaches.
Learn more about the best safety practices for severe weather here, and learn about becoming a trained storm spotter here.