How We Make SnowFeb 11 2015
You’ve probably seen our snow guns pumping out snow since late November so we could triumphantly open Glen Eden ahead of schedule for our beloved pass holders. We wouldn’t have been able to start the season without our snow making operations: the snow guns, and the snow makers who operate them.
Several components are needed to make snow besides water and compressed air—like, wet bulb and nucleators. What’s a nucleator? What’s a wet bulb? These things are important parts of the actual composition of a snowflake, and the climate needed to make snow.
We learn in school that snow is made in nature by the water cycle: warm water turns into vapour that floats up in the sky. Depending on the temperature and density of water, a cloud becomes heavy and snowflakes, or rain, fall down to the earth. Snow guns have the same end goal as nature: to make snow; but, snow guns have a very different scientific means than nature.
Snow guns need water, compressed air, and a special material called a nucleating agent. The compressed air disperses the water into miniscule droplets, shoots the droplets into the air, and keeps the water cold. The interesting part of the mix is the nucleating agent.
In the natural water cycle, pure water vapour in the clouds will not necessarily freeze at the freezing point of zero degrees celsius. Water stays in vapour form until temperatures as low as minus forty degrees! What changes vapour into snow is something we never pay mind to at all: dust and particles floating in the air. Dust and floaty materials are like magnets for water vapour. Tiny water droplets will stick to the dust floating through the cloud and eventually form a snowflake. Think of high school biology: the dust is the ‘nucleus’ of the snowflake molecule! This is why we call it a “nucleator”.
Snow resorts and ski hills, like Glen Eden, use an artificial agent like Snomax. Snomax is made of a type of ice nucleating protein that is harvested from the outer membrane of the naturally occurring bacteria Pseudomonas syringae (don’t worry, the bacteria has been sterilized & irradiated to ensure there are no live bacteria left in the product as an added safety measure). The shape of the protein is ideal for ice crystals to form around and a water droplet seeded with it will require fewer calories of energy to freeze that those seeded with say dust in the air or impurities in the lake water. On most of our snow guns, there is a set of nozzles that mix the air and water to form ice crystals around the Snomax product.
This is what happens inside the snow gun, but the snow gun will simply make rain if we do not have ideal ground conditions. Snow makers operate the snow guns in the appropriate weather depending on the temperature and the humidity. The combined measurement of the temperature and the humidity is called “wet bulb”. The more humidity in the air, and the warmer the temperature, the harder it is to make snow. However! If the humidity is very low, our snow guns can still make snow at temperatures a few degrees above the freezing point! This is how Glen Eden can extend the season on the hills. Our expert Snow makers also know how to toggle with the snow guns to make the perfect powder depending upon the wet bulb temperature.
Written by: Paul Brownridge - Snowmaking Lead