Snowmaking is replicating what mother nature does to produce the white stuff we all love to ski on. Snowmaking is the production of snow by forcing water and pressurised air through a snow gun. Normally it is made by relatively large permanent machinery at many commercial ski resorts. Snowmaking requires a significant level of infrastructure including water storages, pump stations compressors, pipes, electricity supply, hydrants and weather stations.
Process of snowmaking
Snowmaking machines (commonly referred to as ‘snow guns’), make snow by breaking water into small particles, cooling the water by causing the particles to move through cold air, nucleating (the creation of small ice crystals) the particles and distributing the resulting snow on the ground. Sometimes additives are used to help with the process. Due to the nature of snowmaking, it is effectively storing water for the winter, which is then returned back to the environment in the spring thaw - scientists have calculated that roughly 93% returns to the environment.
Types of Guns
In general there are three types of snow making guns: Internal Mixing, External Mixing and Fan Guns. These come in two main styles of makers: air water guns and fan guns. Modern snow guns are fully computerised and can operate autonomously or be remotely controlled from a central location. The aim of modern technology is to improve the reliability of the equipment, maximise production, reduce environmental impact, minimise costs and materials and maximise usage time. There are 2 main types commercially in usage:
Fan Guns are different to all other guns because they require electricity to power a fan and an internal small compressor. The fans propel the water into the air to achieve the hang time and the compressor creates the air needed to operate the nucleator nozzles that are similar to the ones on the external mixing guns. There is a tendency of moving to fan guns due to being cheaper to set up, run and being quieter, however they require electricity and are hard to move. They more efficient than air water guns but can be hard to direct, particularly in windy conditions, some also have a tendency to ice up.
Air water Guns
Are an alternative to fan guns which require a supply of compressed air and water. They are often loud, costly to install due to requiring 2 supplies from a compressor room, and can be costly to operate. However they can be small, compact, mounted in a variety of locations eg on a small trolley, a trailer, on a long pole up high, on top of chairlift infrastructure. They have the advantage of being easy to direct in most conditions, being easy to set up and work on narrow runs. These guns can be further broken up into 2 types:
- External mixing Guns - External mixing guns have nozzles spraying water and air nozzles shooting air through the water stream to break it up into much smaller water particles. These guns are sometimes equipped with a set of internal mixing nozzles that are known a nucleators. These help create a nucleus for the water droplets to bond to. External mixing guns are typically tower guns and rely on a longer hang time to freeze the snow. This allows them to use much less air.
- Internal mixing Guns - Have a chamber where the water and air get mixed together and violently forced out an opening or through holes and fall to the ground as snow. These guns are typically low to the ground on a frame or tripod and require a lot of air to compensate for the short hang time of the water. Some newer guns are built in a tower form and use much less air because of the increased hang time. The amount of water flow determines the type of snow that is to be made and is controlled by an adjustable water hydrant.
The efficiency of snowmaking is largely driven by weather conditions. Low temperature and low humidity increase snowmaking efficiency. The combination of humidity and temperature is called the wet bulb, usually for efficient snowmaking this is below about -2C degrees. Man made snow can be made wet to build a base, this happens early in the season. When finishing up making snow they usually make it dryer to give us a nice finish to dki on. The less water added the drier the snow is. Man made snow cannot make powder.
Snowmaking has had a dramatic impact on the Australian ski industry (and in many other countries), including lengthening the practical season so that it is possible to ski on opening weekend even if its on man-made snow (eg 2008). It improves the reliability, helps with the wear and tear on the various trails particularly important linking trails, and by increasing the base depth can be seen to protect the environment underneath particularly towards the end of the season as it starts to thaw. However it must be realised that snowmaking costs a lot to install, requires a lot of infrastructure, raw materials (including water, air, electricity) and costs money to run (increasing our lift ticket prices). It is too costly to run snowmaking across whole resorts and so is often just used in patches. Snowmaking is a great tool to help us continue to ride snow from seasons start to finish and is helpful in keeping Australia viable. The resorts have done various estimates that show that their snowmaking keeps certain snowmaking areas open a lot more than with just natural snow, hence improving their viability.