Why is it that when it snows, sometimes snowflakes are fluttering, and sometimes snowflakes are fluttering?

Snow is one of the most extensive, universal and main forms of atmospheric solid precipitation. Whether it is summer or winter, the sky is very cold (0 to -40). Water vapor rises to the sky with the airflow and becomes small ice crystals, which in turn form large ice crystals. Slowly, the ice crystals become bigger and heavier, falling from the sky. In the cold winter, the temperature near the ground is very low, and the ice crystals will not melt. When they fall to the ground, it is snow.

Snow particles, also known as graupel, snowball or soft hail, are composed of snow-like ice particles. Compared with snow, when graupel appears, the weather disturbance is strong, which is formed by the collision and freezing of a large number of snow crystals (or snow masses) and Leng Yun drops. The appearance of graupel is generally in the form of array, and the time is short.