Tilling is essentially “churning” up the snow. The tiller is attached to the back of the cat and contains a spinning auger bar and heavy plastic combs. The speed at which the auger bar spins impacts how well we are able to tear apart the snow or ice and lay it down again as corduroy. When there is fresh snow, the tiller does not have to work very hard. When conditions are icy, the auger bar needs to spin quickly to churn the trail surface into fine particles, which the combs press into new corduroy. With hard snow the auger bar has a hard time maintaining speed, so we must keep a shallow depth of cut to keep the bar spinning.