Do the Great Lakes have tides? (2024)

FAQs

Do the Great Lakes have tides? ›

In fact there are tides on the Great Lakes, but the total variation in water level on the largest lakes is less than 5cm (about 2 inches) and is usually overwhelmed by other meteorological effects.

These minor variations are masked by the greater fluctuations in lake levels produced by wind and barometric pressure changes. Consequently, the Great Lakes are considered to be non-tidal. Water levels in the Great Lakes have long-term, annual, and short-term variations.

Do lakes such as our Great Lakes have tides? The answer is yes, our Great Lakes do have tides that occur twice each day, but they are much smaller in scale and barely noticeable unlike the ocean.

This Great Lake doesn't have tides like the ocean; however, periodically the water levels rise and fall by as much as one foot due to a phenomenon called a "seiche" (SAYSH, a French word that means "to sway back and forth").

My understanding is that the Great Lakes all have lunar tides which are relatively in noticeable unless you're actively trying to observe them. However, they do get pretty noticeable wind tides which people often attribute to the former. They are actually noticeable, to me anyway.

On July 13, 1938, five people were killed after a type of tsunami hit Holland, Michigan. Eighty-five years later, researchers say meteotsunamis in the Great Lakes occur more than some may think.

Every body of water is influenced, but the effect is much harder to see in smaller ones. The smallest body of water in which lunar tides have been measured is Loch Ness in the UK, which is 37 kilometres long. Here, the tides have an amplitude of about 1.5 millimetres.

Indeed, tides exist in all bodies of water, even one's bathtub, but is so infinitesmally small, as to be unmeasurable. Even on Lake Superior, the largest of the Great Lakes of North America, the tiny effect of a tide is overcome by the effect of barometric pressure and the phenomenon known as a seiche.

Lake Superior is the world's largest freshwater lake by area (31,700 mi2 /82,100 km2). It is also the coldest and deepest of the Great Lakes, with a maximum depth of 406 meters (1,332 feet). By most measures, it is the healthiest of all the Great Lakes.

Typically, maximum ice cover usually peaks in late February or early March, with the Great Lakes consistently reaching a basin-wide maximum in annual ice coverage of about 53 percent since reliable satellite data collection began in 1973.

Which Great Lake is the cleanest? ›

The average underwater visibility of Lake Superior is about 8 metres or 27 feet, making it the cleanest and clearest of the Great Lakes.

(a) The danger zone. An area bounded on the north by latitude 42°20′30″; on the east by longitude 87°47′30″; on the south by latitude 42°18′45″; and on the west by the shoreline.

The same happens in the Great Lakes, although the largest tides in the Great Lakes are only about 5 cm and are mostly impacted by precipitation, evaporation and runoff.

The Great Lakes are freshwater ecosystems. Traditionally, Lake Michigan, for example, has been a very low-salt lake, with levels around one milligram of chloride per liter of water. Over the years, due to our increased salt use, that level has steadily but gradually climbed up to 15 milligrams per liter.

To me, both Lake Superior and Lake Michigan “look” like the ocean as they are nearly impossible to see across over most of their widths. While the wave heights are smaller than the ocean, the fact that the bodies of water extend to the horizon makes them appear to be “oceans.”

OK, well, they have teeny tiny tides, a difference of a few centimeters on a twice-daily cycle. But the change is so inconsequential that scientists consider the freshwater bodies non-tidal. Because while our lakes are Great, they're comparatively much smaller than oceans. And the gravitational pull isn't strong.

Because of their sea-like characteristics, such as rolling waves, sustained winds, strong currents, great depths, and distant horizons, the five Great Lakes have long been called inland seas.

In fact, lakes do have teeny-weeny tides of a few centimeters in height. Winds, the ferrying of boats, and basic aquatic sloshing would create bigger ripples than the tide itself, making these miniature “tidal waves” almost unnoticeable. Even scientists generally consider freshwater bodies to be non-tidal.