Artificial snow, also known as machine-made or technical snow, is produced to guarantee a reliable winter surface for recreation and sport. Like all forms of water ice, artificial snow melts and returns to a liquid state. However, its manufacturing process gives it unique physical properties. These properties cause it to melt at a significantly slower rate and in a different manner compared to the natural snowfall it is designed to replace.
The Composition and Structure of Artificial Snow
Artificial snow is made almost entirely of water and compressed air, mirroring the basic ingredients of natural snow. The production process involves forcing highly atomized water droplets and compressed air through a snow gun or lance into sub-freezing air. Nucleating agents, such as proteins or mineral particles, are often introduced to help the water crystallize at warmer temperatures than pure water normally would.
The physical structure of the resulting snow particle is the most significant difference from its natural counterpart. Instead of forming the delicate, six-sided, dendritic crystals found in nature, machine-made snow forms dense, irregular, and somewhat spherical ice granules. This rapid freezing process bypasses the complex atmospheric conditions needed to grow intricate snowflakes. The resulting mass is a collection of tiny, packed ice spheres.
How Artificial Snow Differs from Natural Snow
The structural difference between the two types of snow directly impacts their durability and longevity on the ground. Natural snow is light and fluffy because it is mostly air, often being over 95% empty space. This results in a low density of around 30–50 kilograms per cubic meter (kg/m³). In contrast, artificial snow is significantly denser, typically ranging between 400 and 500 kg/m³.
This high density means artificial snow contains far more water mass in the same volume and far fewer air pockets, making it much harder and wetter. Because of this compact structure, it is less susceptible to sublimation, the process where ice turns directly into water vapor. The increased resistance results in a slower rate of melt under identical warming conditions. This durability is why it is often used to create a strong, long-lasting base layer on ski slopes.
The Factors Determining Its Rate of Melting
While the internal structure of artificial snow makes it inherently more resistant to melting, the external environment dictates the actual speed of its decay. The single most important environmental factor is the wet-bulb temperature, which combines air temperature and relative humidity. High humidity makes it more difficult for the snow to cool through evaporation, meaning a lower air temperature is required to maintain the frozen state.
Environmental Accelerants
Direct solar radiation is a major accelerator of the melting process, as the sun’s energy is absorbed directly by the surface snow. The rate of melt is also heavily influenced by the depth and condition of the snow base beneath the surface layer. A deep, compacted base layer acts as an insulator, preventing ground heat from rising and accelerating the melt from below. Wind can also increase the melt rate by constantly bringing warmer air masses into contact with the snow surface, accelerating the transfer of heat and moisture.