This is a February 27 tornado in Marshall, Michigan. Tornadoes are unusual for Michigan early in the year. Most are seen in mid-June to early fall. Image: National Weather Service
By Clara Lincolnhol
The lack of ice on the Great Lakes could cause thunderstorms and tornadoes to occur earlier than usual in the region.
Michigan is expected to see more severe weather in April and May, said Paul Pastelok, a meteorologist for AccuWeather. Historically most of the state’s severe weather begins in mid-June to early fall due to Lake Michigan’s influence on its weather patterns.
And as climate change has led to less ice on the lakes, safety officials are concerned about the increasing risk posed by severe weather. Gov. Gretchen Whitmer designated this week Michigan’s Severe Weather Awareness Week.
Michigan already saw two tornadoes in February, unusual for the time of year, according to the National Weather Service. On average, Michigan sees 16 tornadoes per year, according to the Michigan Department of Community Health.
Atmospheric instability is one of the ingredients needed for severe storm development, Pastelok said. During the spring, the Great Lakes typically act as a stabilizer. Water temperatures and air masses above the lakes are usually much colder than the warmer air masses above the ground.
“You get lake breezes and cooldowns that cause more stability in the atmosphere and so you don’t get as much thunderstorm activity,” Pastelok said
But this spring the lakes will probably act as a de-stabilizer, he said. They’ll warm up more quickly due to the absence of ice. They have a head start, he said.
“This year we think the waters can warm up quick enough that there can be some elevated instability faster in the late spring, so that would cause the thunderstorms to develop a little faster than what we would typically see,” Pastelok said.
The Great Lakes had record low ice coverage this winter, according to the National Oceanic and Atmospheric Administration. Upper Midwest states like Minnesota, Wisconsin and Michigan experienced their warmest winter on record, according to the Prism Climate Group, an organization that generates datasets from climate data.
As storm systems travel northeast, the air above the lake can influence the strength and organization of storms as they pass into Michigan.
That’s why Michigan had two February tornadoes, Pastelok said. “Because of the warm temperatures and the lakes not being ferociously cold, we just had that good setup.”
Other factors also determine if severe storms form, he said. Higher dew points, or the temperature in which air must be cooled for dew to form, and wind shear—which is the change in wind speed and direction as you go higher into the atmosphere are some.
The higher the dew point, the more “muggy” or humid it will feel outside, according to the National Weather Service.
The role the Great Lakes play in weather patterns varies. Sometimes they can dampen the potential for severe weather, while other times they enhance its potential. It all depends on the temperature of the air above the lakes and how it compares to the air above the ground, said Kevin Doom, a meteorologist at the National Weather Service’s Chicago office.
“The lakes can have an effect for sure. They don’t always, but they can have an effect, and not always the same effect,” he said.
Weather forecasters look for where storm ingredients intersect. Warm moist air near the ground, cool dry air aloft, horizontal winds and a mechanism that lifts storms, like a front or dry line—a line that separates moist and dry air, catch meteorologists’ attention, said Harold Brooks, a researcher at the National Severe Storms Laboratory.
“Basically they’re looking for where the ingredients are now and what processes are taking place,” he said. “If one of the ingredients is absent, what are the processes that might bring that ingredient into place?”
Warm moist air from the ground is lifted, cools slightly as it rises and becomes saturated, forming clouds. Moist air is warmer, and less dense than the dry air around it, causing it to rise. Thunderstorms form when warm, moist air rises through cooler, dry air, Brooks said. “It shoots up just like a rocket because it is buoyant.”
Less ice on the lakes impacts the air temperatures of interacting air masses leading to more favorable conditions for thunderstorm development.
When it rains, cooler air is brought down while air higher up becomes warmer. Thunderstorms reduce the gradient of temperatures in the atmosphere and eliminate imbalances, Brooks said.
Although the Great Lakes region does not experience as many tornadoes as the Great Plains states, they do happen and people need to be prepared for severe weather this spring, Pastelok said.
“You always have to have a plan no matter where you are in the country just in case something like that happens,” he said.
Severe weather season starts earlier in other Midwestern states south of the Great Lakes. A deadly tornado outbreak on March 14 produced seven tornadoes in Illinois, three in Indiana and eight in Ohio. Tornadoes in Indiana and Ohio killed three people and injured 58.
Tornadoes can develop with little warning and can be difficult to see, said Pete Duncanson, vice president of training and product development for ServiceMaster Restore, a company that helps communities rebuild after severe weather events.
“It only takes a second for (a tornado) to drop from the air and begin a devastating path,” Duncanson said.
People should pay attention to the weather forecast and have a safety plan for a tornado watch or warning, he said. Plan run-throughs should be conducted throughout the year. Flashlights, durable clothing, a weather radio and non-perishable foods are essentials
Getting underground is imperative, he said. Go to the basement or a storm cellar during a tornado warning. Avoid windows. If you lack a basement, go into an interior room like a closet or bathroom, get low to the ground and put your hands over your head to protect yourself from flying debris. Do not try to film the tornado or outrun it in your vehicle.
If you live in a mobile home, the safest thing to do is leave it, he said. Getting into a low-lying area like a ditch away from trees and other structures is the best thing to do.