More than six metres — 20 feet — of Holiday Beach has been lost in the last six months.
Ongoing erosion means the water laps at the roots of trees, when the sand once extended far beyond the tree line.
Kevin Money, director of conservation services with the Essex Region Conservation Authority, has called the erosion "unprecedented."
"The waves are eating away at the sand and what's being left behind are tree roots and pieces of exposed rock," said Money. "It's creating a lot of hazards for swimming."
Because of that, the conservation authority and the health unit issued a closure notice for Holiday Beach.
"This is fairly unusual," said Money. The high lake levels contributed to the closure, because it obscures the potential hazards.
All the beaches managed by the conservation authority are closed, including Hillman Marsh and Tremblay beaches.
"You see a lot of the trees falling over, the sand disappearing. The lake may be deepening," said Money. "These issues combined lead to problems for potential swimmers.
"We don't want to see any of our facilities closed," said Money. "Our sites are here for the public to enjoy ... that's the point of these areas."
Money said they don't think the beaches will be open this year at all.
"We don't anticipate opening them up right now," said Money. "We'll have to wait for the lake levels recede before we can do another evaluation."
A breakwall already exists at Holiday Beach — beyond that, ERCA is looking at doing more to protect the buildings in these areas, but are generally letting nature take its course.