Abstract: A ski for a vehicle for slidably engaging a surface to be traversed. The ski includes a longitudinally extending runner having a forward portion, a rearward portion and a middle portion therebetween, the forward and rearward portions having a wider lateral width than the middle portion. The forward, rear and middle portions form an hourglass shape, generally. One or more skis may be adapted to a vehicle that includes a frame, a rear drive means for propelling the vehicle along a surface to be traversed and the one or more skis may be attached to a front portion of the frame for slidably engaging the surface to be traversed.