Growing up, my Dad would always have all-season tires on our family cars for their long life and to have a little snow traction. When we moved into colder climates, studded snow tires became a fixture when the ice and snow began to pile up. As technology has improved, most winter / snow tires have a specialized rubber compound that has all but eliminated the need for studs while requiring the tire only be used in cold temperatures.
Some Canadian provinces have laws requiring the use of tires that feature the "snowflake/mountain" symbol for severe winter conditions. To qualify for this rating, the tire's tread design and depth must provide 10% more snow traction than the standard or all-season tire. This symbol (pictured above) pertains only to the tread design and depth and does not guarantee any additional traction on ice or slick conditions compared to an all-season tire. To guarantee a proven performer, it's important to check not only for the right symbol but also the right rubber compound.
Tire Rack has performed many tests in both the snow and on the ice to help customers see the difference in traction levels between winter / snow and all-season tires. In every case, the dedicated snow tire was able to stop in a shorter distance and turn in a tighter radius than the all-season option. If freezing rain or ice are a concern, only the specialized rubber compounds of a dedicated winter / snow tire will do.