The poet used metaphors to describe the sudden heavy snow in the north. This snowy scene is like a spring breeze blowing overnight, and the mountains are full of pear blossoms. This metaphor is novel and apt, vividly describing the snow scene in the north, which not only gives people a strong visual impact, but also makes the cold winter seem to be covered with a layer of warm spring, becoming a classic sentence that has been circulated for thousands of years.