Located on the tire’s sidewall, this “snowflake on a mountain” symbol means the tire is specifically designed for use in severe snow conditions.
Tires marked “M + S” (mud and snow) are “all-season” tires. Don’t buy these, they don’t work.
Side fact: Quebec is the only province, where winter tires are required by law. Your car must have tires with this symbol.
(there’s a nerd joke in here somewhere, about how the tire is also marked with the upload symbol…)