“Who pulled the plug on Goulais Bay,” exclaimed one quizzical post on social media last night.
The post, depicting an extreme drop of almost 4 feet in lake levels was followed by another and yet another picture of the water leaving the shore.
People who have lived in the area for years knew the cause almost immediately; these are the effects of a Seiche (pronounced s-eee-sh).
A Seiche is not a French breakfast tart, no, not a quiche. Seiches are a “potentially dangerous” natural phenomenon according to National Parks Service.
Seiches can be produced by:
- Sudden changes in atmospheric pressure
- Heavy rains
- Surges in glacial meltwater from nearby mountains
- Variations in water density
“A Seiche is a stationary or standing wave that oscillates back and forth like a pendulum in an enclosed or partially enclosed body of water,” states the National Park Service Website. “Seiches in the Great Lakes are typically caused when strong winds and rapid changes in atmospheric pressure cause the water to pile up on one end of a lake. When the wind stops, the water returns to the other side of the lake, often causing water levels to rise quite quickly.”
In the case of Lake Superior, the phenomenon takes about 8 hours to leave and then come back and when it does, things start to float, almost too much.
“Tomorrow we’ll get the report of all the loose stuff floating around and washing up on shore after the water comes back in!,” stated Christine Prescott, one of the commenters.
Locals warned others, including individuals new to the north that what goes out, must come back in and it usually means a storm is coming. Traditionally, the bigger the Seiche, the bigger the storm. Although we didn’t see huge storms here last night, the Upper Penninsula was hammered by strong storms throughout the evening and overnight.
The National Park Service says small Seiches are normal while larger ones can be potentially dangerous and look like storm surges. The event is Nature’s way of redistributing nutrients from deeper water to the top.
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