Grooming and Snowmaking
Laurentian Ski Hill’s Outdoor Operations staff work tirelessly to ensure our hill is always in the best conditions for skiing and riding. Unfortunately Mother Nature sometimes makes the job more difficult, so we have a variety of tools to make sure the slopes are always pristine. The fact that our hill faces south creates additional challenges, the spring sun works against us keeping the hill open .
Although they work late at night or early in the morning and are often unseen, Laurentian Ski Hill’s groomer operators take great pride in their work. They work to reshape the hill, pushing snow that has been moved through the day back to where it is needed and breaking up ice, leaving the smooth courdory surface that skiers and boarders love.
Frequently Asked Questions
Why is grooming needed?
Every day, skiers and snowboarders push snow down the hill as they turn, and scrape the snow down to ice underneath. Combined with the varied weather we may recieve throughout the winter, the hill would turn into an icy, bumpy mess without frequent grooming. The groomer functions to push snow back up the hill, filling in low spots and breaking up ice. The groomer also helps extend the ski season by pushing out the piles from snow making and covering up spots where the snow will melt through.
When is the hill groomed?
The hill is usually groomed every day, but this depends on the weather and snowmaking progress. Usually the hill is groomed immediately after closing to allow time for the snow to firm up before the morning, but grooming may start later if the temperature is changing or precipitation is forecast. Grooming may also start later in the night to allow more piles to accumulate from the snowmaking process. You may see the groomer out during the day from time to time, often in the park.
What do you use to groom the hill?
It takes a very specialized piece of equipment to be able to push snow uphill while pulling the tiller. The groomer is a tracked vehicle with a snowplow like blade on the front and a tiller on the back. The operator has precise control of the blade’s angle in all directions, allowing them to contour the hill a they drive. In 2012, we replaced our old Bombardier PlusMP with a 2006 Prinoth BR350, as the old machine was reaching the end of its useful life. The new groomer is more powerful and has a full set of ice picks, allowing it to push snow up hill much more effectively. The blade is also capable of movement in more directions, making shaping the park features easier. Customers have been noticing the increased quality of our grooming with the new machine, and the staff love its increased abilities and ease of use.
How is the courdoury surface created?
Behind the groomer is the tiller. Like a garden tiller, the teeth on the tiller spin at high speed, breaking up clumps of snow and ice and levelling the surface. Behind the teeth the groomer drags heavy rubber mats with plastic combs that leave the characteristic texture as the are dragged across the hill.
Snowmaking is a vital component of our hill’s operations. Snowmaking allows us to run our seasons consistently, the most important factor in ensuring the long term success of our hill. We want to make sure the hill is open in time for the holidays, won’t have to close due to rain in January, and will be able to remain open throught the March school break. A consistent season also guarantees jobs for our many seasonal staff and drives tourism, supporting the local economy. Snowmaking is a difficult job, with the combination of water, ice, slush and cold temperatures coming together to make for a hostile environment to work in.
In preparation for the 2011-2012 season, Laurentian Ski Hill Snowboarding Club recieved a grant of $74,400 from the Ontario Trillium Foundation for upgrades to our snowmaking system. The new equipment is more energy efficient and allows more snow to be made at marginal temperatures, so the hill can open more terrain earlier in the season.
The grant allowed us to invest in the following equipment:
– 12 Johnson Controls Snow Waterstick airless snowguns
– 11 Ratnik SkyGiant VI High Efficiency Air/Water Snowguns
– 1 Yamaha VK540 snowmobile designed for ski hill operations
– Assorted additional snowmaking equipment and supplies
This new equipment greatly increases our snowmaking capacity, and will supplement and replace a variety of older, less efficient snowguns.
System Construction: 1998
Water Capacity: 560 gpm (gallons per minute)
Water Pressure: 500 psi (pounts per square inch)
Air Capacity: 400 cfm (cubic feet per minute)
Air Pressure: 100 psi (pounds per square inch)
Number of Hydrants: ~40
Number of Snow Guns: 25-30
Maximum Number of Guns in Simultaneous Operation: ~15, weather dependant
Frequently Asked Questions
What is artificial snow made of?
There is nothing artificial about the snow we make. It is simply air and water, just like natural snow.
How does machine made snow differ from natural snow?
Machine made snow is created using the same principles as natural snow, with small droplets of water freezing into ice crystals. Machine made snow is usually denser than natural snow, similar to the way snow packs down over time. Since we rely on snowmaking to create a base that will last throughout the season, this denser snow helps resist melting and is easier to groom. When made and groomed properly, machine made snow in combination with some natural snow is as good as or better than the real thing.
What temperatures can you make snow at?
Snowmaking relies on wet-bulb Temperatres. Unlike your thermometer at home which measures the dry-bulb temperature, wet-bulb temperature includes the humidity as a factor. Similar to how your skin feels colder after getting out of the shower, the humidity plays a large role in determining if snow can be made and its quality. We generally start making snow when the wet-bulb temperature drops below -8 degrees celsius. At 20% humidity, that’s only -4 degrees celsius! We can make snow in even warmer temperatures, but the quality is greatly diminished and the process is energy intensive.
How do you make snow?
A simple explanation is that air and water are pumped uphill through a series of pipes. A snowgun is connected to a set of hydrants on the hill, like a faucet, and the air and water move up the gun and out nozzles at the top. Outside the gun body, the air stream crosses the water stream, breaking it up into individual droplets that float to the ground, freezing into tiny ice crystals.
Although relatively simple in concept, snowmaking is a highly technical process. In the pumphouse at the bottom of the hill, a large air compressor pumps air through an air cooler, lowering its temperature to just above the freezing mark. At the same time, water is drawn in through a pump and pushed up the hill. The water and air pipes run next to each other with hydrants attached to allow the connection of snowguns. The snowmaking staff takes care to ensure there is always water moving through the system in order to prevent the pipes from freezing.
At the hydrant, snowmaking staff connect the guns to the hydrants where snow will be made. Air and water run up the body of the gun and are forced through nozzles arrainged at the tip. Depending on the type of gun, the nozzles may be arrainged differently but the conecpt is the same regardless. The compressed air shatters the stream of water creating many tiny droplets, called nuclei. These small droplets start to freeze in the cold air and fall to the ground. On some of our newer snow guns, additional nozzles spray larger droplets over the smaller nuclei, building up the size of the ice crystal and increasing the efficiency of the system. The rapid expansion of the compressed air coming out of the nozzles also causes the temperature of the air to drop, as proven using the ideal gas law, PV=nRT, where P is pressure and T is temperature. This localized cooling effect also helps produce snow.
One problem encountered by a snowgun is the freezing point of water. Pure water does not freeze until it is very cold, approximately -40 degrees celsius. Small particles, called nucleating particles, are needed to start the formation of an ice crystal. All water contains some nucleating particles, even treated drinking water, however in order to increase the efficiency of our system we add more.
When making snow, snowaking staff are contsantly on the hill checking and adjusting guns. By varying the amount of water and air being pumped through the gun, the consistency of the snow can be changed as the temperature varies. The guns must also be moved frequenly as piles of snow are created, and re aimed should the wind change to prevent the snow from burying the gun, hoses, hydrants or other fixed items.
When do you make snow?
When the snowmaking system is running, snowmaking staff are on hill 24 hours a day to check and adjust guns. Most guns are moved in the early evening immediately after the hill closes to make snow in new areas.
Do you add anything else to your water?
Yes, we add Snomax snow inducer. Pure water does not freeze until -40 degrees celsius. Small nucleating particles are present in water to start the freezing process, and Snomax increases the number of particles in the water. Snomax is a protien derived from P. Syringae bacteria, and its hexagonal shape is incredibly efficient at starting ice crystals. Snomax allows us to start snowmaking at higher temperatures and produce more snow at lower temperatures. Snomax is environmentaly safe and occurs naturally in plants and vegetation.
What are you doing to be more efficient?
Trying to replicate mother nature is an energy intensive and therefore expensive process, so we’re always looking for ways to be more efficient.
In marginal temperatures, the amount of air required to produce snow is quite large, however as the temperature drops the ratio of air to water required to make snow gets lower. Before the 2011-2012 season, our snowguns didn’t allow us to change this ratio very precisely, wasting energy and snowmaking capacity as the temperature dropped. Our new Ratnik SkyGiant VI snowguns that were purchased in 2011 have four sets of nozzles, one set that produces small nuclei using air and water, and three sets for just water called stages, with operation of stage two and three optional. At marginal temperatures with only one stage running these guns are no more efficient than the older models, however as the temperature falls the additional stages can be opned up, increasing the flow of water and reducing the ratio of air to water while continuing to produce the same quality of snow.
Snomax is another way we increase our efficiency. Snomax reduces the amount of water required to produce snow at low temperatures, resulting in an increase in efficiency.
In 2011, we also added another new type of snowgun to our arsenal. The Waterstick is a water only snowgun that relies on Snomax snow inducer to provide nucleation, rather than air. The height of the snowgun also increases the hang time of the water droplets, giving them more time to freeze without the help of the expading compressed air. Look for these silent giants making teriffic snow on the hill this winter.
We also work hard in the off season to reduce the amount of snow making that is required. By filling holes, removing obstacles and controlling the flow of water down the hill, we require less snow to cover the terrain and reduce the amount of snow that melts. Thanks to the help of Gap Construction in 2011 and Bruman Construction in 2012, the terrain park now has a much more consistent slope that requires less snow production to fill holes and dropoffs
Why does it look like so much water is being lost into the air?
A combination of factors sometimes makes it appear like a large amount of the water that comes out of the snow guns is simply floating away. In actuality less then 5% of the water we use for snowmaking is lost to evaporation, and it can be hard to see the larger droplets of water descending from the nozzles of the snowguns. The combination of cold days with low humidity and the expanding compressed air causes the cloud to be more visible, and when the surface level winds are low the cloud tends to rise up vertically and is visible across the city. You may also notice that some of our snowguns appear to lose less water than others. Our new high efficiency snowguns have a higher water to air ratio in cold temperatures, reducing the size of the cloud and the amount of snow lost, and the new water only snowguns barely produce a noticeable cloud at all.
How do you decide when and where to make snow?
The decision to make snow is complex and based on a variety of factors, and starting or stopping the snowmaking process is time and labour intensive. When making the decision whether or not to make snow, hill management will consider the current temperature, daytime highs and nighttime lows, long term temperature forecasts and the chance of rain in the future, as well as the impact of holidays and other factors. It doesn’t make much sense to create lots of snow in a November cold snap when there is a good chance it will rain again in December, but starting too late would mean opening day might have to be pushed back. Snowmaking stops when the forecast temperature stays below -25 for too long, as the guns and hoses freeze up in the cold. Snowmaking also shuts down for holidays, and in both cases it takes time to drain the system and blow the water clear from the hoses and snowguns.
Snowmaking generally starts in the beginner hill each year, followed shortly by Slingshot allowing the hill to open. Focus then shifts to opening the Terrain Park and parts of Maples. As the park nears completion Steve Omischl is next, and when complete guns are moved to finish Maples and open Aeroplane. The last place to have coverage is usually under the top of the chairlift, but this depends on annual conditions.
How much of your hill has snowmaking coverage?
Our snowmaking system allows us to make snow on 100% of our skiable terrain, except the glade of course.
What are those doors for under the chairlift?
The doors under the top of the chairlift just before the unload ramp cover the valves to turn on the snowmaking in the terrain park and beginner hill. Without shutting them off when no snow is being made there, the pipes under these hills would freeze easily as they are only buried a few inches under the ground.