FILE - Russia's Alexander Terentev, right, and Czech Republic's Michal Novak, left, crash during a men's cross country sprint quarter final race at the FIS Nordic World Ski Championships in Oberstdorf, Germany, Feb. 25, 2021. Olympic and World Cup race organizers are already used to needing snow-making equipment to create a ribbon of white through the forests as natural snowfall becomes less reliable. Skiers and experts say manmade snow has a higher moisture content, making it ice up quickly. (AP Photo/Matthias Schrader, File)

FILE - Norway's Vibeke Skofterud, left, escapes a crash involving Sweden's Norgren Johansson, right, and Poland's Paulina Maciuszek in the women's 15-kilometer pursuit cross country skiing event at Whistler Olympic Park on February 19, 2010, at the 2010 Vancouver Olympic Winter Games in Whistler, B.C. Many top Nordic skiers and biathletes say crashes are becoming more common as climate change reduces the availability of natural snow, forcing racers to compete on tracks with the manmade version. (AP Photo/Andrew Vaughan, CP, File)

FILE - Germany's Tim Tscharnke falls in front of Russia's Nikita Kriukov, right, after making contact with the skis of Finland's Sami Jauhojaervi in the men's classical-style final of the cross-country team sprint competitions at the 2014 Winter Olympics, Feb. 19, 2014, in Krasnaya Polyana, Russia. Olympic and World Cup race organizers are already used to needing snow-making equipment to create a ribbon of white through the forests as natural snowfall becomes less reliable. Skiers and experts say manmade snow has a higher moisture content, making it ice up quickly.(AP Photo/Dmitry Lovetsky, File)