Snow making was previously thought only to be capable by ski resorts with expensive commercial equipment. Resorts produce man made snow on a massive scale using thousands of gallons of water per hour and need much colder temperatures. With the same basic concept, you can make snow in your own backyard.
There are three important variables needed for snow making:
- R/h (Relative Humidity)
That sound's pretty simple doesn't it? Well making snow is a little more complicated, but easy to understand once you've learned the basic fundamentals.
Let's start with temperature. Many ask to make snow, even in the middle of the summer. Unfortunately, this is impossible unless you have low enough temperatures. Well how does Hollywood do it? Commercial “snow” that you see on movie sets, or commercial promotional videos actually starts out as a block of ice, that is shaved and blown over an area. This type of “snow” melts easy and is very impractical. However real snow can be made at temperatures above freezing, up to 39 degrees Fahrenheit.
Since man made snow is almost five times denser than natural snow, it takes longer to melt so you'll have more time to enjoy it.
Although the air temperature is important, the key player is called the Wet Bulb Temperature, also known as the “wet bulb”. The wet bulb is lowest temperature that can be reached by evaporating water into the air while consideration of the dew point. Snow can be made at a wet bulb temperature of 27 degrees or below, however these are considered “marginal” conditions meaning less quality snow. A wet bulb temperature of 20 degrees or below is perfect for snow making. For example, if the air temperature is 35 degrees Fahrenheit with 20% relative humidity, you have a wet bulb temperature of 26 degrees and snow making is possible. Let's take another example, measuring the air temperature at 28 degrees Fahrenheit with 100% relative humidity and you have a wet bulb temperature of 28 degrees which is inadequate for snow making. Remember, the wet bulb will always be less than or equal to the temperature.
Without knowing humidity, it will always be possible to make snow 27 degrees F or below.
Now you must be asking yourself how do I calculate the wet bulb temperature? Not all weather gauges or stations will display the wet bulb temperature but we offer tools to help. We highly suggest using a weather station to accurately measure temperature and humidity for accurate results. Snowpacked offers a FREE weather alert system that will send you an email in advance when your area will be cold enough for snow making conditions. A wet bulb calculator, chart, and weather station recommendations can be found on our weather tools page.
Although humidity is measured in several ways, we'll only focus on the relative humidity. Relative humidity (R/h) is the amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature. Surely we've all seen it somewhere or another but what does this mean and why is this important to snow making? Liquid water contains high heat energy concentrations and must be released through an evaporation process. With a high humidity atmosphere, there is less room for water or snow to evaporate. When the humidity is lower it allows more space for water or snow to evaporate.
Remember, the lower the humidity the better.
Snowguns use special water nozzles that size the pressurized water droplets precisely enough for the heat to be removed. These nozzles are referred to as "Bulks" and operate at pressures from 300-500 psi. Too large of a droplet would not allow enough heat to be removed, resulting in ice after it freezes. If your water droplets are too small, you risk the chance of too much evaporation with nothing to show on the ground.
Snowguns use another nozzle that consists on solely air, or a high concentration of air with very minimal water. These nozzles are referred to as "Nucs" or nucleating nozzles that operate at pressures from 70-90psi with at least 4.3CFM (cubic feet per minute). This added air increases the rate of evaporation. A air compressor supplies high volumes of air to the nucleating nozzle.
More CFM is always better.
A common term is called "Hang time" the amount of space, time, and height water droplets have to cool. The higher your snowgun is in the air, the better quality snow you will have. Mounting your snowgun too high is not recommended when any wind speeds are present. The wind will carry your snow and drift to where you don't want it.
Water of course is the main ingredient in snow making. Determining the amount of snow you can make is calculated by your flow rate of your pressure washer measured in GPM (Gallons per minute).
The more GPM you have, the more snow you can make.
The actual pressure of the pressure washer is irrelevant in snow making, as the orifice size of bulk nozzles will determine water pressure. Not absolutely necessary, colder water greatly aids snow making especially in marginal conditions. Some snow makers use ponds or pools as reservoir for their water which is an added cooling benefit. If this is available to you, be sure to install a filter on your pressure washer to protect the pump from contaminates or particles that can destroy your equipment. You will also need a booster pump to push the water from it's source. Pressure washers use the water to cool and lubricate the pump. Running your equipment dry without water will destroy your equipment. It is not recommended that you use a water source that is colder than 36 degrees Fahrenheit. This increases the chance of freezing in your lines and can also destroy your pump.
If you have found any of this information to be confusing, visit our Questions and Answers page.