Making snow in the mountains
There are years when Mother Nature sends early snow our way, and there are years like 2020, where it stays dry and mild into late October (we've skied as early as October 8th in the past!). What do ski areas do when opening day is looming and there is no snow in sight? Well, they make their own.
How does this all work? Let's dive in.
The Ingredients
Let's start by clarifying that man-made snow is not fake snow. It is the real deal, just a different crystal pattern...the only ingredients that you need are:
Water
Air
Some resorts may add special proteins to the water in order to help it freeze, but in the right conditions, you don't need it.
The Machinery
Ok, so we have water and air, that is easy enough. But how do you take a pond or hydrant of water and turn it into snow? Snow guns. If you've skied back east, or early in the season out west (or next to a newly forming terrain park), you've heard the deafening hiss of snow guns blasting out a fine white flurry. The snow guns are key to the process...along with the staff who makes sure the guns are doing what they are supposed to.
The Conditions
Unfortunately, you can't fire up the snow guns when it is 70 degrees out and get snow. Wouldn't that be nice? You need dry, cold weather for the best man-made snow. Snow makers rely on what is called the "wet bulb" temperature. Hang tight while I geek out for a minute. Feel free to skip down if you aren't curious about the science behind this :)
The wet bulb temperature is the lowest temperature you can achieve while evaporating water into the air. When the air is dry (low humidity), it wants moisture. So when water is sent into the air...say from a snow gun...some of the water molecules evaporate. Evaporation requires energy (heat), so a small amount of heat is taken out of the air around the molecules. This lowers the temperature of the air which gives us the "wet bulb" temperature. The lower the humidity, the more water can evaporate into the air (stealing heat), and a lower air temperature can be achieved.
https://www.snowathome.com/pdf/wet_bulb_chart_fahrenheit.pdf
So we want cool temperatures and low humidity.
The Process
Today is the day! The air temperature is cool, humidity is low, and the snow guns are loaded with water and ready to fire up. What happens when the guns are turned on?
Snow guns will use either compressed air or a fan to disperse the water from the guns into the sky...that is why they are so darn loud! The water shoots out of the gun, is mixed with compressed air or meets a fan, and the tiny droplets are shot high up into the air. This allows enough time for some of the droplets to evaporate and others to freeze before they hit the ground as man-made snow. The snow is then allowed to cure (dry out) for about 24 hours before a snow cat comes by and moves it to where it needs to be.
Man-made snow tends to be a bit denser than natural snow so it sticks around longer and makes a good base for the winter. It takes awhile for snow to melt, even when the temps warm up during the day, which is how the snow made at night sticks around.
Where you make the snow matters as well. You don't really want to be make snow on a South/West facing run that gets blasted by afternoon sun. North and East runs will be cooler, less sun baked, and hold the snow better.
Did you make it this far? Was this as fascinating to you as it was to me? I love knowing how things work so I hope this was a fun read for you. Send some cold weather thoughts our way out here in Colorado, we could use some right now!
Stay Wild and Free,
Michelle