Iowa Code § 321G.18: Negligence.

The owner and operator of a snowmobile are liable for any injury or damage occasioned by the negligent operation of the snowmobile. The owner of a snowmobile shall be liable for any such injury or damage only if the owner was the operator of the snowmobile at the time the injury or damage occurred or if the operator had the owner’s consent to operate the snowmobile at the time the injury or damage occurred.