The recent thaw followed by a deep freeze has the Essex Region Conservation Authority asking the public to say away from re-frozen or elevated rivers, lakes, and standing water.
Director Tim Byrne says the recent thaw freed up ice-flows in waterways throughout Windsor-Essex, causing natural dams in some areas. Those dams may have raised water levels.
He says bitterly cold winds can freeze up to 2-inches of water every 24-hours.
"Probably the best observation would be on River Canard where the ice surface has ruptured and actually had ice move both over and under intact ice on the waterway," he says.
Eventually the blockages will pass and the water will flow out from beneath the fresh ice - that's when Byrne says conditions can become treacherous.
"The interesting phenomenon that occurs is that water that's being artificially held up ice bridging is going to quickly start to drain out," says Byrne. "At the same time, ice is forming on the surface."
Byrne tells AM800 News people venture onto the ice at their own peril.
"Keep livestock, pets, and small children away from areas that look like a nice big pond that was created by that run-off from that thaw," he says. "It will be a calm looking flat surface, but in most cases will not be supported by water immediately underneath it."
He says recreational vehicles like snowmobiles should be weary of conditions on rivers and lakes, as shorelines are likely to be experiencing "ice bridging."
Byrne advises everyone to avoid going out on recently thawed then refrozen areas of rivers, lakes, and ponds until further notice.