snow·mo·bile 
(snōmō-bēl′, -mə-)
(snōmō-bēl′, -mə-)n.
A small motorized vehicle with skilike runners in front and tanklike treads, ridden by straddling a seat and used for driving in or traveling on snow. Also called snowmachine.
[SNOW + (AUTO)MOBILE.]
snowmo·bile′ v.
snowmobile