06/04/2026
Great historical piece by the HLF.
If you’ve ever spent a delicious summer afternoon anchored at the Sunken Island, you might think it’s pretty darn good: a shallow, walkable oasis of sand and smooth glacial stones, surrounded by deep, clear blue water…Zzzzz.
BUT, have you ever wondered why the Sunken Island is there? How does a shallow island just 'exist' in the South Basin?
History lesson: back to the Ice Age we go!
Higgins Lake was carved out during the last Ice Age by massive, retreating glaciers which were over a mile deep. As these giant sheets of ice melted and shifted, they didn't just dig a uniform bowl - they scoured the bedrock unevenly, creating complex underwater topography!
* The Deep Basins: The glaciers gouged out two massive, deep pockets (our North Basin, dropping down to 135 feet, and our South Basin, dropping to around 100 feet).
* The ‘Sunken Island’: The Sunken Island is actually a glacial moraine ridge—a high point where the moving ice deposited a massive pile of compressed gravel, sand, and heavy boulders before melting away.
Over the millennia, as the land rebounded from losing the crushing weight of the ice, the lake levels shifted. Thousands of years ago, Higgins Lake was actually much higher than it is today. As water levels naturally fell and stabilized into the lake we know today, that underwater glacial ridge remained just a few feet below the surface!
