What Snow Makes the Best Snowballs: Physics and Meteorology of the Ideal Snowball The quality of a snowball is not a matter of luck, but a direct result of meteorological conditions that determine the physical and mechanical properties of the snow cover. Creating an optimal snowball requires an understanding of the phase state of water in the snow mass, the crystal structure, and the processes occurring during mechanical compression. 1. Key Parameters: Temperature and Humidity The two main factors determining the "stickiness" of snow are air temperature and the amount of liquid water in it. Their interaction is described by the concept of snow-water equivalent (SWE) and the stages of snow metamorphism. Ideal snow ("snowball" or "packaging" snow): Forms at temperatures close to 0°C (-2°C to +0.5°C) and high relative humidity. In these conditions, some snowflakes are on the verge of melting. When compressed: Sharp points of crystals melt under pressure and the heat of the palms. The formed thin film of water acts as a natural glue. Upon subsequent freezing (already in flight or when thrown), this "glue" crystallizes, bonding the snowball. Such snow is pliable, sticky, forms dense, monolithic, and heavy snowballs capable of flying far and causing "considerable damage." Cold, dry snow (below -10°C): Consists of hard, brittle crystals with minimal amounts of unfrozen water. When compressed, crystals do not melt, but break and crumble. The forces of friction and mechanical adhesion between the fragments are insufficient to form a strong ball. The result is a loose, powdery snowball that falls apart in your hands or in flight. Its albedo (reflective ability) is maximum, visually making it very white, but practically useless for play. Wet, "heavy" snow (temperature around 0°C, thaw): Contains an excess of liquid water (more than 10-15% by mass). It is easily shaped when molding, but becomes not a snowball, but an ice ball. It is too dense, not aerodynamic, soils gloves, and ... Read more