In the forest in NW Montana. our 1 to 1-1/2 lane road has a few sections, including a sharp S-turn, exceeding 18 degrees. Don'tt need studs in town or generally to get to the ski hill but they sure help, especially at intersections and turns where the heat from tires slightly warms the snow which can instantly freeze if cold enough creting a nice patch of ice. We see people driving rentals cars slidding through intersections a lot. The snow has a lot of moisture mostly due to the influence of flathead lake about 23 miles to the south. It is the largest freshwater lake west of MS.