Winning or losing a medal in the Olympics is often determined by fractions of a second. In cross-country skiing and the biathlon, the winning formula isn't just determined by the athlete or the course. It's decided in a small, heated room filled with waxes and science.
Have you wondered why skis slide in the first place? It's not just because snow is slippery. It's about physics.
As a ski glides, the friction creates a tiny amount of heat, melting the very top layer of snow into a very thin film of water. The ski isn't sliding on snow — it's sliding on that water. The challenge is creating the perfect amount of that water.
It's a balancing act Eric Pepper, Nordic Program Director at Ski and Snowboard Club Vail and a veteran cross country team U.S. ski technician, knows well.
"If it's colder and drier, you're usually trying to combat some sort of mechanical friction," Pepper said. "If it's warmer and wetter, you're usually trying to combat suction."
Enter the wax room. The goal is to choose the perfect ski wax based on the weather conditions at the time. The choice of wax is a big deal — and it's a closely held secret.
"A lot of the waxes that are used for like the national teams at somewhere like the Olympics or the World Cups, a lot of them don't even have labels on the packaging. They're blank," Pepper said.
Weather conditions determine the type of wax. When Pepper steps onto a course in the morning, he's got weather measurement tools with him.
"Did it rain? Did it snow? Is it warm? Is it cold? What are the characteristics of the course that you want to try to accommodate for?" Pepper said.
Ultimately, choosing the right wax comes down to three main things: temperature, moisture, and snow type. Pepper goes out with a thermometer and other sensors to measure these things in the snow. Skiers then ski the slope with different types of wax to see what's faster and grippier.
Temperature considerations
If the temperature is colder than 20 degrees, the snow crystals are hard and abrasive, and a hard wax is chosen.
The sweet spot is between 20 and 30 degrees.
When the snow is warmer than 30 degrees, there's more moisture in the snow, and a soft wax is used that repels water. Too much water acts like a suction cup and pulls on skis.
Moisture matters
Fresh dry snow has a lot of friction, which requires harder wax. Wet slushy snow needs softer water-repellent wax. Old dirty snow requires wax with extra protective chemicals.
Snow type is crucial
For the Olympics, most snow is artificial. Man-made snow crystals freeze into sharp, angular shards. They're denser, harder, and more abrasive — a critical factor in choosing a wax that can withstand the grind.
What's the hardest condition to prepare for?
"The historically challenging condition is like just above freezing and new falling snow," Pepper said. "You're slamming your wax book down on the table when things are being challenging."
In the battle for every tenth of a second, the race is often won before it even begins — in the wax room.
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