How is the weather like snow formed? Use pictures or words to express.

Snow is divided into light snow, medium snow and heavy snow. The legend and text are as follows.

Water vapor in the air meets some tiny floating dust in the sky and then begins to condense. At a certain temperature, it begins to crystallize and grow, forming snowflakes, and when its weight increases to a certain extent, it begins to fall, forming snowfall. If the temperature continues to decrease, it may form hail, and if the temperature increases, it may form rain.