More than 90% of Italy’s ski slopes rely on snowmaking. The technology has transformed skiing, making sure there is a season even when nature does not deliver. But how does it actually work? What does it cost? And what does it do to the environment?
How artificial snow is made
The physics
Artificial snow (more accurately called ‘programmed’ or ‘technical’ snow in Italy) is made by spraying a fine mist of water when the temperature and humidity are right. The droplets freeze in the cold air and form small ice grains, similar to natural snow.
What you need
To make snow you need:
- Temperature: below -2°C (wet-bulb temperature)
- Relative humidity: the lower the better. At 30% humidity, snow can be made at -1°C
- Water: lots of it, usually taken from purpose-built storage reservoirs
- Electricity: to run the compressors and pumps
Two types of snow gun
High-pressure guns (lances): shoot water up to 10 m into the air, where it freezes. They are the most common, the cheapest and the quietest.
Fan guns: use a large fan to blow the droplets further. They cost more but work better when temperatures are borderline.
Snowmaking in Italy in numbers
| Figure | Value |
|---|---|
| Slopes with snowmaking | Over 90% |
| Water needed for 1 km of slope | 1,000-3,000 m³ |
| Cost per hectare of snow | €2,000-5,000 |
| Energy per m³ of snow | 2-5 kWh |
| Snow depth per cycle | 20-30 cm |
What it costs the resorts
Snowmaking is one of the biggest costs a ski resort has:
- An average resort spends €500,000-2,000,000 a year on snowmaking
- The equipment (guns, pipes, reservoirs) costs millions of euros
- Snowmaking accounts for 25-40% of the total cost of running the slopes
Is artificial snow the same as natural snow?
No, but the difference is smaller than you might think:
| Feature | Natural snow | Artificial snow |
|---|---|---|
| Crystal shape | Star-shaped flakes | Round grains |
| Density | 50-100 kg/m³ | 350-500 kg/m³ |
| Feel on the slope | Soft and light | Firmer, more compact |
| How long it lasts | Melts sooner | Lasts longer |
| Skiing quality | Excellent | Good to very good |
Because it is denser, artificial snow stands up better to skier traffic and sunshine. That is why slopes prepared with it stay consistent for longer.
The environmental impact
Snowmaking has a significant impact.
Water
An average resort uses 100,000-300,000 m³ of water a season. To limit the impact, many resorts have built storage reservoirs that collect rain and meltwater and return it to the natural cycle.
Energy
Energy use is high, but falling:
- New snow guns use 30-40% less energy than those of ten years ago
- Some resorts run on renewable energy (hydroelectric, solar)
- Automated systems adjust production to the temperature and humidity
Additives and chemicals
In Italy, artificial snow is made only from water and air. No chemical additives are used, unlike some resorts in North America that add nucleating agents.
The future of snowmaking
With climate change cutting natural snowfall at lower altitudes, snowmaking matters more every year. Current innovations include:
- IoT systems: real-time temperature and humidity sensors to fine-tune production
- Snow farming: storing winter snow through the summer under insulating sheets
- Multi-purpose reservoirs: used for snowmaking in winter and irrigation in summer
- New-generation guns: more efficient, quieter and able to work at higher temperatures
For more on the climate challenge facing the Alps, read our article on climate change and the future of skiing.