If you follow the Ontario Provincial Police on social media, you may have recently seen them share the hashtag #NoIceisSafeIce as a reminder to folks to be cautious on lake ice. Whether ice-fishing, snowmobiling, or skating, activities that take place on ice always carry a risk of breaking through the ice and drowning. Carefully observing weather conditions, tracking ice thickness, and wearing safety equipment are all part of staying safe while having fun on ice. But this is becoming more challenging as the environmental conditions that control ice thickness shift as a result of climate change.
Researchers from York University collected drowning death data from ten northern hemisphere countries and found that the largest number of drownings occurred when winter air temperatures were between -5˚ C and 0˚C. As climate change leads to warmer winter air temperatures, the risk for winter drownings may increase as well.
The research also showed that children under nine years old accounted for almost fifty percent of the drownings that did not involve a vehicle. Drownings occurred when children were exploring, tobogganing, and playing with friends on ice.
“I was really shocked by this finding,” says Sapna Sharma, associated professor in the Department of Biology at York University and lead author of the research paper. “It speaks to the importance of water safety for kids.”
Research shows that lakes have been rapidly warming in the last twenty-five years, but human behaviour has not adapted to meet the resulting environmental changes. Ice is most dangerous in the shoulder seasons, and climate change is changing the dates for ice formation and melting.
“Back in the 1980s, lakes may have frozen in November or early December,” says Sharma. “By Christmas, you could be using the ice for skating and ice fishing. Because of climate change, the date of ice formation is later and later. The ice is not as thick at Christmas as it was in the past.”
Even in the darkest months of winter, a warming climate is changing the way ice behaves. “Because of these extreme events we’re experiencing, we now get really warm days in the winter, or a rain event. That decreases the structural integrity of the ice,” says Sharma.
Just looking at the ice is not a way to determine how thick it is, says Barbara Byers, public education director at Lifesaving Society, a non-profit charity devoted to drowning prevention that contributed data to the study. “You need about a week of cold weather, about -10˚ C, for things to freeze. Not one night.”
Those conditions are trickier to come by in a mild winter. Ice that is undergoing cycles of freezing and thawing is not safe ice, says Byers. If thawing occurs, people need to restart the timer and wait again for a full week of cold weather before venturing out on the ice.
While it may seem counterintuitive, snow is also detrimental to ice thickness. Fallen snow acts as a blanket, warming up the ice below, says Byers. “Say you’re at a cottage and you want to play shinny or you want to go skating. You should clear off the snow, and ensure the ice is really hard for seven days. Don’t just shovel off the snow and say we’re good to go.”
One of Sharma’s recommendation to prevent future winter drownings is to include ice safety in children’s swimming lessons. The Lifesaving Society’s Swim to Survive school program for Grade 3 students in Ontario does just that. The program teaches students survival swimming skills in a pool and includes a classroom lesson plan on ice safety.
Parents need to treat ice-covered water as if it were a swimming pool, adds Byers. Kids should never be left unattended near or on ice.
For the snowmobilers and icefishers out there, personal flotation devices and hypothermia-protective clothing should be worn to keep the wearer warm and floating should they fall into water.
We can also look to other winter-loving countries for winter safety techniques. One tool that should be embraced by Canadians are ice claws. These are ice picks that can be worn on light rope lanyards for easy access. Should the unthinkable happen, they can be stabbed into the ice and used as a brace to pull the upper body out of the water. “In Sweden, where they love being out on the ice to skate, they all wear these ice picks around their necks,” says Sharma.
Read more: Q&A weather and ice for skating