Old hardpacked snow doesn't throw up in the air, it just lets the knobs sink in but not the whole tire, it gives amazing grip even if the tires aren't studded, we often ride that kind of snow here in Iceland, it amazes me how steep a hill one can climb in that kind of situation, a lot of fun. I have a gopro and in my images the lens exaggerates a lot.
At around 0:48 in
this vid the hill looks crazy steep, it is steep believe me, but not as it looks on the vid from the gopro