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Rising temperatures are creating new challenges for winter sports. Shorter winters and unpredictable snowfall are forcing athletes to ski and snowboard on artificial snow more often. At the same time, natural ice on ponds and lakes is becoming unstable and dangerous. Top athletes are adapting their equipment and techniques to handle these new conditions. Their stories offer important lessons for anyone who enjoys winter activities in a changing climate.
In warm or dry winters, many ski competitions take place on artificial snow, such as here at Val-Louron, a ski resort in the French Pyrenees, in March 2023. It was an unusually warm month worldwide.
Sarah Cookler remembers a specific race in March 2023. She was coaching Team USA in ski mountaineering. This intense sport involves racing up and down mountains while wearing skis. The race happened in the Pyrenees mountains of France. "It was probably around 40 to 50 degrees Fahrenheit," Cookler said. The entire course was covered only with artificial snow. It felt wet and slick. Dry, yellow grass lined the edges of the track. Her athletes usually train in Utah where the snow is deep and dry. They had never faced such warm and tricky conditions before.
This situation is becoming more common. As natural snow seasons get shorter, athletes are training and competing almost entirely on machine-made snow. For ice sports like skating and hockey, warmer winters mean outdoor ice forms later and melts much earlier. This creates a much riskier environment. As a result, many athletes now rely on indoor arenas to practice and compete. What these competitors learn about adapting to new conditions can help everyone stay safe while having fun in the snow and ice.
The 2022 Winter Olympics in Beijing used only artificial snow. To a casual viewer, it might have looked like natural snow. However, the athletes could feel the distinct difference. Artificial snow has unique properties because of the way it is made. Snow hydrologist Noah Molotch explains the visual differences. "It's got kind of a beige color," he says. "It's not yellow snow! But it does have a slightly darker appearance."
Machines create artificial snow when the air is very cold. They spray a fine mist of water into the air. The tiny droplets freeze into hard, round beads before they even hit the ground.
Steffan Brennstiener of Team Switzerland (left) skis during the Mixed Team Parallel heats on February 20 at the Beijing 2022 Winter Olympics games. All outdoor snow events there, including this one, were held on artificial snow. Competitors had to adjust for how it behaves somewhat differently from natural snow.
Natural snowflakes form high up in clouds. They come in many intricate shapes, like stars and plates. These complex shapes trap a lot of air. This makes natural snow fluffy and light. Artificial snow beads are much denser and contain significantly less air. "Those beads don't have as much air as a natural snowflake," Molotch notes.
This physical difference changes how the snow behaves on the ground. Powder snow is soft and loose. Artificial snow is harder and more tightly packed. This creates a very firm and smooth surface. Skis can race across it much faster. "Artificial snow is less likely to get rutted by skis," Molotch says. However, this hard surface means that falls are much more painful. "There is no give in that snow," Cookler adds.
Before a race, athletes carefully inspect the course and adjust their gear. For the race in the Pyrenees, Cookler's team had to prepare very carefully. They filed their skis to sharpen the edges for better control. They also applied a special type of wax.
Artificial snow, Cookler points out, "rips the wax off a lot faster and is abrasive on the skis." Because the day was warm, her team chose a hydrophobic wax. This type of wax repels water. It prevents a "suction cup" effect that can happen in wet snow. They also attached climbing skins to their skis for better grip on the uphill sections of the track.
Technique must change as well. "Going downhill when snow is soft and slushy is going to be different than when it's firm and icy," Cookler observes. On soft, artificial snow, she advises skiers to be "a little softer with your turn so you don't dig in as much."
Noah Molotch (right) discusses how to measure snow depth in a snow pit with a student (left) on Niwot Ridge in the Colorado Front Range. Snow depth measurements help scientists forecast weather and estimate how much water supply an area might get from melting snow.
Because winters are warming, artificial snow is now common in competitions. A study published in December 2024 found that winters in the Northern Hemisphere warmed noticeably between 2014 and 2023. Countries lost an average of seven winter days during this period. In Europe, which is home to many ski resorts, the loss was over two weeks per year. Resorts now often use snow machines to build a reliable base of snow.
Molotch advises recreational skiers to ask exactly where a resort uses artificial snow. A sudden change from natural snow to artificial snow can easily lead to a crash. He has suffered injuries from years of skiing on hard snow. When asked how he adjusts his technique now, Molotch says: "I ski away from it."
Different combinations of temperature and humidity produce different snowflake shapes and sizes. Kenneth Libbrecht, California Institute of Technology
For ice athletes, most high-level competition happens indoors. However, ice quality in arenas can vary significantly. Kelsey Koelzer is a college ice hockey coach. "When you first step out there, you can tell if the ice is going to be hard or soft," she says. Hard, cold ice is faster and requires less effort for hockey players. Soft, warmer ice is better for figure skaters, as it grips their blades more securely.
Arena technicians control the ice temperature and thickness to suit each specific sport. However, a survey conducted in 2024 found no scientific consensus on the perfect ice temperature. This means that quality differs from arena to arena, which teams must account for when they travel.
The bigger change is happening outdoors. Warming winters are making natural ice on lakes and ponds less stable and safe. Hydrologist Joshua Culpepper led a major study on lake ice. His team used computer models to look at data stretching back to 1850. They project that by the end of the century, there could be 5 to 29 fewer days each year when lake ice is safe for skating or walking. The exact number depends on how much winters warm in the future.
Team USA's Corrine Higgins locks into her skis after pulling off their skins at the transition area in the 2023 International Ski Mountaineering Federation's World Youth Cup. Skiers match their equipment with racecourse conditions. Higgins won gold in the under-16 women's category of the vertical race.
Perhaps more troubling, ice thickness alone may no longer be a reliable safety guide. Some states say that 10 centimeters (4 inches) of new "black ice" is safe. Black ice is clear and solid. But Culpepper's research found that "white ice"—formed when snow melts and refreezes on top—is much weaker. "When you have more white ice... it's about 50 percent weaker than black ice at the same temperature," he explains.
Climate change is leading to more white-ice conditions. "If you're out on a lake that had a small layer of black ice and then it snowed a lot," Culpepper says, "you need twice the recommended ice thickness" for safety.
It is still possible to enjoy outdoor skating safely. It just requires more caution and knowledge. Retired champion figure skater Angelina Huang loves skating on frozen lakes for the freedom it offers. "A lot of the lakes that I tend to skate on stretch 10 to 15 miles long," she says.
She stresses safety above all else. Huang trains yearly in ice knowledge and self-rescue techniques. She advises less experienced skaters to use managed ponds where experts check the ice regularly. She also says to never skate alone.
Culpepper and his colleague Sapna Sharma offer similar advice. Children should always skate with an adult. An adult should test the ice thickness first. "Have an adult test the ice before going out," Culpepper advises. Sharma adds, "if you're going to go out on [lake] ice, learn how to swim in cold water."
The ice conditions ideal for hockey are too cold for figure skaters. They also differ from those preferred for curling.
Coach Kelsey Koelzer sums up the situation perfectly. Enjoy skating in nature, she says, but "always have your guard up." In a warming world, understanding the changing qualities of snow and ice is key to enjoying winter sports safely.