Lake Superior can sound like a cupboard full of breaking glass when its ice starts to move. On 13 February 2016 Dawn M. LaPointe of Radiant Spirit Gallery filmed thin plates of lake ice sliding onto the shore at Brighton Beach in Duluth, Minnesota, where they piled up in a shifting, chiming heap of translucent edges.
Lake Superior ice stacking at Brighton Beach, Duluth
LaPointe first noticed sheets of ice pulling away from the shore at Canal Park, Duluth’s busy lakefront district. Guessing that the moving ice would come ashore somewhere else, she headed to Brighton Beach and arrived in time to film the sheets breaking against the shore.
Her notes describe sustained south-westerly winds in the days before, which had broken up the ice and set it drifting. The finished film runs about two minutes, cut from roughly two hours of recording, and LaPointe states that the clips play at normal speed. The movement and the sound are exactly as she saw and heard them.
What causes ice stacking?
Ice stacking, sometimes called an ice shove or ice push, happens when wind or currents drive floating lake ice towards the shore. Once the leading edge hits rock or sand, it has nowhere to go. The sheets behind keep pushing, so the ice fractures into plates that slide over one another and pile up, and on big lakes and Arctic coasts the piles can reach 12 metres (40 feet). Scientists list several drivers: persistent strong winds, currents, changes in water level and the expansion of ice when temperatures rise quickly.
Thin ice gives the most musical results. The plates are glass-clear, sharp-edged and light enough to tinkle and clatter as they collide, which is why videos like LaPointe’s are so often compared to breaking glass or wind chimes. Thicker ice pushed ashore makes a deeper grinding and cracking sound. The National Weather Service documented a separate Lake Michigan event on 28 January 2014: a steady west wind pushed ice away from the Illinois and Wisconsin shores, and by afternoon the lake had almost entirely opened up, as satellite loops and a webcam on Chicago’s Harrison Crib recorded.
Lake Superior in winter
Lake Superior is the largest of North America’s Great Lakes and the largest freshwater lake in the world by surface area, about 82,100 km² (31,700 square miles). It is also the third-largest by volume, behind Baikal and Tanganyika, and reaches 406 m (1,333 ft) deep. All that water holds heat, so the lake freezes over completely only about once every 20 years. In 2014 ice covered 92.5% of the Great Lakes at the peak, and Superior itself reached a record 95% in 2019. In most winters the ice is partial and keeps moving with the wind. That restless, broken ice is what produces shoreline shows like this one.
Duluth, at the lake’s western end and twinned with Superior, Wisconsin, is the farthest-inland port reached from the Atlantic through the Saint Lawrence Seaway, and a fine place to watch winter ice. Check the wind forecast: a strong onshore wind after a cold spell is the moment to head for the shore.
Watch from solid ground: moving shore ice is unstable, so enjoy it from the beach or the rocks above it. For another side of freshwater ice, explore Lake Baikal’s winter ice photographs, compare it with ice born on land in our iceberg photography story, or watch snow in motion in Christian Mermoud’s dense avalanche in Valais.
Related reading
- Frozen Soap Bubbles: ZALUSKArt’s Close-Up Winter Film
- Frozen Flowers in Minnesota: A Familiar Material Becomes Brittle
- Jenny Ayrton’s Miniature Glass Worlds: Everyday Scenes in Cast Glass
- Chris Ratzlaff’s Frozen Soap Bubbles in Calgary
- Coloured Ice Orbs: A Winter Craft with Water and Balloons
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