The blue in Lake Michigan and Lake Huron is sediment brought to the surface when strong winds churned the lakes. The green in Lake Erie and in Lake Huron's Saginaw Bay is algae, which builds on the surface when winds are calm.
Safe for Swimming? The answer is, it depends. Under the right conditions, Lake Michigan is safe for swimming. But this lake can also present dangerous, even deadly, conditions for swimmers.
Invasive zebra mussels are mostly responsible for the increased clarity of Lake Michigan. About 25 years ago, Lake Michigan's water was somewhat of a brownish-green color, very different from the pristine blue-green appearance of today.
Should you shower after swimming in Lake Michigan? Take a shower: Bathe yourself after swimming in a lake in order to maintain hygiene and stay clean. If bacteria has not entered your body, it may be actively resting on your skin, creating a rash or finding an open cut to infect.
Additionally, since rain events tend to lead to elevated bacteria levels in the water column, we advise that people avoid swimming after a large rain event.
Not only is this lake massive - spanning 307 miles in either direction - but its shores also run parallel, causing unique wave shapes. The shapes of these waves are what contribute to rip tides, which are one of the most dangerous things swimmers can encounter in the water.
A north-northeast wind has pushed the warmer surface water along the Michigan shore back toward the middle of Lake Michigan and brought up colder water from well beneath the surface. This process is called upwelling.
The lake's formation began 1.2 billion years ago when two tectonic plates moving in opposite directions left a giant scar—an event now known as the Midcontinent Rift. Less than 15,000 years ago, melting glaciers filled the giant basin, and Lake Michigan came to be. The lake's maximum depth is 925 feet.
Blue Lake, New ZealandThe Blue Lake is the clearest lake in the world. New Zealand is well-known for its natural beauty, with mountainous terrains surrounding crystal clear lakes whenever you hop out of the city. But the country is also famous for having the clearest lake in the world!
The United States Environmental Protection Agency, for example, describes them as “vast inland freshwater seas.” A seminal 2017 paper in Limnology and Oceanography, authored by some of the most influential researchers studying the lakes, also refers to them as 'inland seas.