Whether or not you believe in global warming and climate change, here are some facts to consider:
- 19 of the 20 hottest years have occurred since 1980
- Worldwide temperatures have warmed one degree Celsius over the 20th century
- More than 20% of the Polar Ice Cap has melted in the past 30 years
Climate change can result in more air pollution and problems with water supplies as precipitation patterns change. The effects are much greater at extreme latitudes on both ends of the earth and at higher elevations. We don’t know with certainty what the future will bring, but that doesn’t mean you do nothing. Just the opposite. Develop a well thought out and logical plan for your resort.
Intelligent snowmaking investments will continue to help stabilize your mountain resort business. Adapting strategies and practices in anticipation of less natural snow, and less snowmaking time under the condition of higher snowmaking temperatures coming in smaller windows, will force your team to improve. The goal is to improve your energy intensity or the energy used per cubic foot of product produced.
As the famous scientist Pascal claimed, “. . . given the possible outcomes, the upside of being prepared and ready for a fearsome event surely beats the alternative.” Weather volatility is here and is not going away, and our ability to forecast the weather remains difficult for more than about seven days out. Your continuing investment in snowmaking and working with companies like SMI that have experienced, talented people and products can only help improve your chances for success.
So, what can you do to improve snowmaking? Consider the following:
- Secure water rights now
- Add water supply and storage now
- Invest in new snowgun technologies that aremuch more energy efficient
- Add fans to wide trails to get 100% width, even in “bad years”
- Invest in automation for your plant
- Invest in automation for snowguns and maybe hydrants as an option
- Buy a good, reliable, fast-acting weather system like SMI’s SmartSnow using aspirated weather stations
- Our industry theme for snowmaking should follow NSAA’s policy to reduce, educate and advocate for change
- Promote the fact that snowmaking returns over 80% of the water used. We are not consumptive. Stored water as snow during the winter saves it for future use in the spring
- New snowmaking technologies have better water-to-snow conversion rates and are much more effective energy users
- Snowmaking allows health and fitness benefits to millions in winter who go out side and enjoy
In general, snow quality is defined by snow density or percentage water content. Density is mass per volume in kg/m³ or #/ ft³. Water content is measured per snow depth or volume of melt water within a given volume. Here are some density examples:
| MATERIAL | KG/M³ |
|---|---|
| Sea Water | 1030 |
| Fresh Water | 1000 |
| Ice | 920 |
| Snow | 50 - 600 |
| Air | 1.3 |
Ice floats on water due to being lower density. In snowmaking, we often think of snow quality in terms of the classic snowball test of squeezing water out, or the sleeve test on a cold jacket – does it splat or bounce?
You Have Snow Quality Options
In SMI’s automation programs we use 10 snow quality setting options with one being the driest setting. Wet bulb, water temperature, water pressure and water flows are all considered in the settings. Here is a density summary table with 5 general setting examples for water content relative to snow quality your resort might use.
| Quality | Water Content | Description |
|---|---|---|
| 5 | > 50% | Wet snow that is slushy |
| 4 | 42 - 50% | Base snow, wet in marginal |
| 3 | 35 - 42% | Good skiable snow |
| 2 | 25 - 35% | Light and dry, snowballs flake off |
| 1 | < 25% | Very dry, can't make a snowball |
Snow quality definitely impacts snow volume, while nucleation and water droplet mixing, hang time and cure time also affect the snowmaking process. As you know, there is a big difference in cost and productivity at 29°F (-1.5°C) and 0°F (-18°C). We suggest you discuss snow quality on a regular basis throughout the time of snow production. Understand the costs and capabilities within your snowmaking system and snowgun fleet for making dry snow or base snow at different wet bulb conditions.
One of the areas that we all need to be reminded about is that more water through a snowgun does not directly result in more snow on the ground. Over the past few winters SMI has been testing new nucleation technologies and nozzle types and positions. We have tested in conditions between 29°F (-1.5°C) and -2°F (-19°C) with water temperatures of 34-35°F (2°C) and frozen water content between 24% and 55%. More than 100 tests have been completed.
Traditional Air/Water
- Uses more than 200 cfm (5.67 cmm) of compressed air per snowgun
- Internal mix nucleation
- Typical short tower or sled mount
- High energy and noise
- Good in marginal conditions with decent snow throw
Fans
- Simple nozzle PoleCats and Pumas to multi-nozzle Wizzards
- Various carriage and tower mounts
- Excellent overall snow production
- Excellent throw
- Good energy usage and low noise levels
Low and Moderate Energy Towers
- Uses less than 180 cfm (5.0 cmm) of compressed air per snowgun
- Typical 6m to 9m tower mount or 3m to 5m sled mount
- Internal or external mix nucleation
- Good energy usage
- Possible limited marginal and cold condition production
- Possible limited throw
- SMI’s Viking at 20 cfm to 180 cfm Fans
- Simple nozzle PoleCats to multi-nozzle Wizzards
- Various carriage and tower mounts
- Excellent overall snow production
- Excellent throw
- Good energy usage and low noise levels
Water Sticks
- Water only towers that use additives for nucleation
- Decreased popularity due to limited marginal temperature production
- Limited throw
- Additive cost a factor
Selection Factors
- Snow production in various temperatures and humidity levels
- Throw
- Sensitivity to winds
- Ease of operation
- Noise
- Appearance – are towers acceptable
- Tower heights
- Tower positions - trail edge or middle
- Water pressure requirement
Cost Considerations
- Initial capital cost for equipment and system
- Energy costs
- Labor costs
- Maintenance costs
- Additive costs
- Transport costs
- Grooming costs to push snow out from piles
We encourage resorts to consider snowgun performance and snow quality under multiple conditions such as: in mild years, typical years, cold years, and under good wind and bad wind conditions. What type of spacing of snowguns is required to connect the piles? What types of throws versus trail widths are needed?
As you can see, there are many factors that go into the snowgun selection process. We want you to educate yourself on as many parts of snowmaking as you can to help make a better informed decision.
Understand existing snowgun flow rates at 28°F, 24°F and 20°F wet bulb, and do not just believe the manufacturers. Go out and measure water and air flows with flowmeters. And check snow quality and snow density. What happens if conditions move up or down 2°F?
Mounts for snowguns matter. Generally, the taller the tower, the better the production - up to about 40 feet in height. Any taller and the support mechanisms become quite significant. Wind impact is also a big consideration above 40 feet.
Air flow rates have a direct cost correlation to energy costs so define air volume closely.
What is the range of performance for your snowgun fleet?
- On/off snowguns
- One valve and flow steps
- Multiple valves and flow step
- Infinite adjust of air and water
What happens to snow quality?
- How does your on/off work when it is marginal or cold?
- Sweet spot is likely about 4°F of range!
These are some areas for your team to focus on as the snowguns utilized remain the biggest predictor for costs.
As you evaluate snowmaking at your resort, focus on the variables you can control.
- Where to Start? Define your operating costs:
- Energy, labor, maintenance, depreciation, additive and transportation
- What is your grooming cost to push out the piles?
- Historical water volumes
- Historical hours of operation
- Historical average temperatures and humidities by month
- Inventory water and air systems
- Inventory hydrants and snowguns
- Inventory snowgun types and mounts
- Work Through Start Up Scenarios:
- Who is defining the opening strategy? Trails, depth, full width?
- Are you making snow on the right trails guest desire?
- Or is your focus the easy to make snow on trails?
- Do you have the correct snowguns on trails?
- Are you using lowE on 250’ wide trails?
- How long does it take to change trails and startup snowguns?
- How much water can you convert to snow at 28°F wet bulb, 25°F wet bulb?
- Evaluate Existing Snowgun Fleet:
- Evaluate Snowgun Options
- Fixed Position Various Portable
- Grooming Costs
- Automation Levels
What are the water and air flows consumed at three different temperatures? (see "Understanding Snow Gun Flow Rates" in previous section)
(See "Snow Gun Choices" in previous section)
Moving from portable snowguns to fixed position snowguns can result in huge savings on primary trails. When you consider set up time, burying snowguns, digging out snowguns and the time to take down and put away or park, these costs and difficult work environment are a real challenge. The labor and lost snowmaking time generally justify a fixed snowgun on primary trails.
Now it certainly depends on winds, trail, priority, existing infrastructure, snow volume per snowgun and other factors to help determine if fixed position snowguns will be effective. SMI has many manual customers that can start 150 fan snowguns in less than an hour with five snowmakers. The key is they are towers with the cords, hoses and orientation ready to go. Add automation and they can be started even faster.
Some larger resorts with ground air guns on sleds or tripods may make three ribbons on a 200’ wide trail. In other words, they set up on the far 1/3 of the trail and make snow, then move all 50 guns over 60 feet to hit the middle third and so on. Why not just add tower fans that throw the entire width?
Are you using lowE towers or small throw air snowguns with little throw on 200’+ wide trails? So the snow is basically positioned in a big butterfly pile 20’ to 70’ from the snowgun. So grooming times are huge to push it across the trail to get to full width. So instead of 30 hours cat time to open, it may take 90 hours. At $100/ hour that is $6,000. Using oscillating tower fans will cut time down dramatically.
The majority of snowmaking snowgun automation is with fixed position snowguns. Consider the height of the tower and the convenience of access for service and maintenance. Automation factors to consider are many and include starting, adjusting and stopping/draining. Is the start full open or throttling with pressure control? Does the adjustment involve valves and pressure control? Does the snowgun shutdown and drain on fault or power loss? Is there intelligence at the snowgun? Can it run without communications or a link to the master computer? What is the flow range of the snowgun at your resort? What type of communications are used? Hardwire, fiber optic and radio modems are commonly used today in snowmaking.