Ice shoves are the hidden danger of the Great Lakes
It’s important to be aware of the weather conditions that could lead to ice shoves, to protect yourself, others, and your property.
Ice shoves are a dangerous phenomenon that can happen in the winter and springtime along the shores of the Great Lakes—or any large body of water, for that matter, such as Lake Winnipeg in Manitoba.
The Great Lakes are incredibly large bodies of water, used for shipping goods and ores around the world. Their shores are also home to many Ontarians—with communities and several large cities sitting along the coast, so it’s important to be aware of how and when ice shoves can form.
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Whereas an ice jam is caused by mounds of ice plugging up a waterway, flooding surrounding areas, ice shoves are large chunks of ice that are rapidly pushed on shore. The ice can pile to as high as 12 metres!
Ice shoves, also called ice tsunamis, require three main factors to form: fluctuating warm temperatures, high sustained wind speeds, and a portion of open water.
These conditions came together on Jan. 27, 2025, when a strong low-pressure system over Quebec sent powerful winds along a cold front into southern Ontario. A bout of Arctic air a week prior had helped Lake Erie increase its ice cover to 75 per cent, but a sudden rise in temperatures ahead of the powerful front helped to weaken the ice sheets over the lake—thus, creating the risk for dangerous slabs of ice to plow onto the shoreline.
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Another reason ice shoves are a hidden danger is because they can strike after sunset—meaning you, quite literally, would not see them coming.
You may be able to hear them coming, however, as the breaking and movement of the ice can cause loud crashing, crackling, and booming sounds.
Ice shoves are rapid and unpredictable, moving at rates of up to several metres per minute. Being hit by the ice could severely injure a person, and any buildings struck could sustain significant damage. They have even been known to move vehicles!
Thumbnail image of ice shoves on Lake Nipissing taken and submitted by Brady Dyment.