The Eastern Canadian blizzard of March 1971 was a severe winter storm that struck portions of eastern Canada from March 3 to March 5, 1971. The storm was also nicknamed the "Storm of the Century" in Quebec. The event included the worst 24-hour snowfall on record in the city of Montreal with 43 centimetres of snow falling on March 4, for a total of 47 centimetres, until the one-day record was broken again on December 27, 2012. Higher terrain in eastern Quebec received as much as 80 centimetres. Heavy snowfall was also recorded in eastern Ontario and northern New Brunswick as well as parts of the Northeastern United States. The storm itself was responsible for the deaths of 17 people in Montreal along with numerous other injuries directly and indirectly attributed to the blizzard.

A blizzard is a severe snowstorm characterized by strong sustained winds and low visibility, lasting for a prolonged period of time—typically at least three or four hours. A ground blizzard is a weather condition where snow is not falling but loose snow on the ground is lifted and blown by strong winds. Blizzards can have an immense size and usually stretch to hundreds or thousands of kilometres.