GRAND RAPIDS, Mich. (WOOD) — Tornadoes are the most violent weather phenomenon on the planet.
Looking at the last 30 years, Michigan averages about 16 tornadoes annually. The 10-year average is 13 tornadoes each year.
Tornadoes can strike in any month of the year but are most common in the spring and early summer months. The second most common time of the year for tornadic activity is typically in the fall for Michigan.
The most violent tornadoes in our state’s history have occurred in the month of April. The Hudsonville-Standale tornado of 1956 happened on April 3.
The Hudsonville-Standale tornado was an F5, thought to be an EF5 by today’s updated scales. The parent storm that produced this devastating tornado spun in off of Lake Michigan and immediately dropped a second tornado in Saugatuck. This was originally rated as an F4, likely an EF4 now.
The tornadoes that touched down in Saugatuck and in the Hudsonville-Standale area are large reminders that tornadoes will strike almost anywhere.
Lake Michigan will not stop a tornado. Tornadoes can, and will, travel through valleys, lakes, cities and hills. There have been two tornadoes in the last 20 years to have touched down in the United States above 10,000 feet elevation. One was at 11,900 feet elevation in Colorado in 2012. Another in 2004 at more than 12,000 feet in California.
HOW DO THEY FORM?
Scientists are still working to learn why tornadoes form. The leading theory is that there is such a massive pressure difference between the surface and the sky that there must be an equalizing force to correct the imbalance. A tornado — a hyper-local occurrence of relatively very low pressure — is thought to be the fastest way the atmosphere can “fix” the imbalance.
Classic tornadoes need moisture, lift, instability and shear to form. Wind shear occurs when wind is moving at one direction or speed at the surface, and a different direction or speed aloft.
If wind shear is strong enough, it can create a horizontal circulation above the surface. When a source of lift is involved, like sunshine, this can turn the horizontal circulation vertical! Storms forming in this environment are more likely to have spinning updrafts and are more likely to be able to produce a tornado.
In Michigan, we frequently can see brief weak tornadoes that have poor instability but a lot of shear. These typically are brief, small tornadoes, but they can still do damage! In fact, most of the tornadoes that have touched down in Michigan in the last several decades have been weak according to the Enhanced Fujita scale.
One of the most memorable is the EF1 tornado that tore through Portland, Michigan in 2015.
WHERE IS A SAFE PLACE TO BE DURING A TORNADO?
In the event of a tornado, be sure to get into a sturdy structure and stay away from external windows or walls. In the event the building you are in does not have a basement, an interior bathroom or closet is a good option to stay safe.
Bike helmets and blankets are recommended, as one of the biggest hazards with tornadoes is flying debris.
If you cannot get to a solid structure, there are alternative ways to stay safe. Storm Team 8 Meteorologist Emily Schuitema has a great guide on how to take cover.