The vast majority of us who live near Lake Michigan take it for granted, but have you ever taken the time to think about just how big the waves in Lake Michigan really are? At 1,255 feet deep, Lake Michigan is the fifth-largest of the Great Lakes in North America, covering nearly 56,000 square miles of real estate. It’s a stunning body of water, with waves that range from gentle lapping, to choppy and even dangerous, depending upon the weather conditions.
In terms of specific size and height, there’s no one answer that’s applicable to all Lake Michigan waves. But, it’s often said that when the waves get “big”, they range anywhere from one to six feet in height.
The size and shape of the waves depends on a lot of factors. The Lake is particularly susceptible to wind shear, so the direction and speed of the wind takes a leading role in dictating wave size. That’s why large storms — or even a small gust of wind — can often cause choppiness, sending waves crashing over the shoreline.
According to research conducted by the University of Wisconsin-Milwaukee’s School of Freshwater Sciences, high waves encountered on the lake during storms can trigger strong winds and waves, which can exceed 20 feet in height in some cases. Other observers have noted that rogue waves have been known to reach as high as 30 feet under certain circumstances.
Aside from wind direction and speed, another major factor in wave height is the unique geography of the Lake. Due to both its size and its considerable depth, it creates a sort of “ripple effect” when waves reach the shoreline on either side. These waves often become concentrated by the lake’s shallower waters, leading to high, choppy waves even when the wind speed outside the lake is relatively low.
Of course, this isn’t something that applies simply to Lake Michigan. All of the Great Lakes have large, powerful waves that can prove hazardous not only to shoreline dwellings, but also recreational boaters. Bette LaPorte, a professor of freshwater science at Michigan Technological University, emphasizes that these waves should be respected and monitored with care, given the unpredictable nature of the lake’s elements.
Finally, University of Wisconsin physicist Mark Svoboda suggests that being aware of the advantages and disadvantages of the region’s geography and seasonal weather patterns is key to staying safe in Lake Michigan. When extreme conditions exist, boaters should have a plan of action ready before venturing out into the lake.
The Effects of Wind on Lake Michigan Waves
It stands to reason that the most important factor affecting the waves in Lake Michigan is the wind. If a strong storm rolls in from the northwest, for example, choppy waves can quickly follow, often reaching several feet in height. Furthermore, the size and shape of these waves depend largely upon the direction of the wind relative to the shoreline.
Therefore, boaters should plan their route based on the wind direction, as well as the prospect of future shifts in the wind’s path. Since storms can cause sudden and drastic changes to wind strength and direction, it’s best to be prepared with a safety plan before and when heading out onto the lake.
Also, some parts of the lake have steeper water slopes than others, and certain areas can be more prone to stronger, more dangerous waves. Of course, the northernmost parts of the lake are known to have the most dramatic swells and conditions, as the lake’s surface area becomes increasingly smaller, increasing the odds of dangerous waves.
For those visiting the lake, it’s important to remember the deep waters, strong currents, and occasional extreme waves of Lake Michigan. Be sure to keep a safe distance from shore, and be prepared for rapid weather changes.
Also, the lake has a somewhat unique bottom topography in various places, so it may be helpful to familiarize yourself with the depths and slopes of the lake bed prior to heading out on the water, as those elements have an impact on wave height.
The Great Lakes Circulatory Effect
Another integral element of Lake Michigan waves is the “Great Lakes Circulatory Effect.” Essentially, this is a phenomenon that happens when the waves interact with the shallow bottom portions of the lake, creating a concentrated effect.
In this situation, the great depths of the lake slow down the bottom portions of the wave, creating highs and lows. These uneven swells then combine with the wind, creating huge and powerful waves compared to the lake’s usual lapping.
The Circulatory Effect is common during the summer months when some parts of the lake are comparatively shallow; it happens when the lake’s large body of water meets the Great Lake’s shoreline, as the waves concentrate around the outer edges of the lake.
Natural and Artificial Barriers that Impede or Enhance Wave Height
There are several natural and artificial barriers that are built around the lake that can either enhance or impede the intensity and size of the lake’s waves. For example, offshore breakwaters are designed with the intention of limiting wave intensity before it reaches the possible shoreline destination.
These constructions have the propensity to deflect incoming waves, and in the process, provide added geographical protection for shoreline residential buildings. Furthermore, since these structures can block incoming waves, smaller, more depressed waves often form in their wake.
On the flip side, riprap and revetments are structures also used to reduce waves. Both of these tend to focus more on shortening a wave’s length, rather than its height. Such construction work can be costly, but is a necessary measure to protect properties and avoid erosion.
In terms of natural barriers, the south and central parts of the lake have several reefs, coves, and other local protrusions that have the potential to reduce or even distract the intensity of certain waves. By opening “gaps” to the waves, they are often broken up, leaving them with less energy as they meet land-side destinations.
The Importance of Staying Informed
It’s not just skippers, sailors, and other boaters who need to stay informed of the waves in Lake Michigan. Landside property owners and visitors should also be mindful of the possible dangers that high Lake Michigan waves can bring, especially when large storms occur.
Keeping up with local weather alerts, and monitoring respected sources of tide information, can help people stay ahead of the game. Certainly, it’s best to be prepared when below-normal temperatures, high wind speeds, or other unusual conditions exist.
Furthermore, it’s worth noting that periodic weather updates, as well as big hazard alerts, all fall under the jurisdiction of the US National Weather Service. Such official government bulletin can provide important safety notices regarding increased wave heights and strong rip currents.
For many of us who live in the Great Lakes region, the lake’s waves can often times be taken for granted. But, the truth is that they should be respected — and with strong winds, the waters of the lake can become rapidly dangerous and unpredictable.
Measuring the Waves
Measuring Lake Michigan waves is done in much the same way as other bodies of water. Buoys in the lake collect and record data regarding wave frequency, high and low water levels, and local currents.
These tidal data points are then shared with the National Data Buoy Center, the US National Ocean Service, and the US Geological Survey’s Earth Resources Observation and Science Center. All of these sources publish detailed reports concerning the lake’s waves and other conditions.
By staying up to date with these resources, boaters and others affected by the lake’s waves can ensure maximum safety and enjoyment. Such sources also help people adjust plans as necessary, and can provide warnings ahead of extreme weather events.
Forming a Plan of Action for Possible Dangers
Given the unpredictable nature of Lake Michigan’s waves, those venturing out onto the lake should have a plan of action ready. Being aware of the advantages and disadvantages of local geography and seasonal weather patterns is key. This plan should also include personal protective equipment, such as a personal flotation device, a well-stocked medical kit, and a first-aid book.
Furthermore, those on the lake should always remain aware of the local weather conditions, and when necessary, keep an eye on forecasts for the next few days. Additionally, radios and radiospeakers (or other communication devices) should always be aboard in order to keep track of any ongoing storms, or other sudden changes that may arise.
Finally, it’s important to note that the lake’s waves can be quite treacherous during certain weather windows, and that they should always be respected. Equally important is the fact that the waves can provide an exciting way to spend the summer — so long as they are monitored with care.
