Code of Federal Regulations Title 43. Public Lands:  Interior § 43.423.37 Winter activities

(a) You must not tow persons on skis, sleds, or other sliding devices with a motor vehicle or snowmobile, except that you may tow sleds designed to be towed behind snowmobiles if joined to the towing snowmobile with a rigid hitching mechanism, and you may tow disabled snowmobiles by any appropriate means.

(b) You must not ice skate, ice fish, or ice sail within 300 yards of dams, power plants, pumping plants, spillways, stilling basins, gates, intake structures, or outlet works.

(c) You must comply with all other posted restrictions.