This has been the best winter for skijoring for decades. Races every saturday and sunday.
The video is from the Amateur Championship of Latvia.
It isn't so crazy... Some motorcycle riders are / were professionals and now are catching some adrenaline between motocross seasons... As for skiers, I can bet that any of instructors here are better skiers... Skis - which isn't pity to scratch :D
About tires... Studless tires with a softer compound of rubber... They come from Russia. I guess there are quite many people who ride their bikes in winter.
Snow/ice tracks now are made in many fields, just pay 10$ and you can make some laps with your everyday car...