Snow gun calculator: how much snow per hour and per night
Enter the gun and the weather. The box shows how much snow it lays per hour and per night, and at what wind.
An estimate for planning, not a manufacturer’s figure. The gun’s own chart beats this calculator. Assumptions are listed below.
How a gun makes snow
- Cooling tower chills the water
- Water under pressure
- Nucleators: ice seeds
- Nozzles: fine droplets
- Fan throws the plume
- Drops freeze in flight
Formulas and assumptions
Wet bulb: psychrometric equation solved by bisection with Magnus saturation pressure, sea-level pressure from the forecast.
Snow = water × (1 − losses) × 1000 / density. Water = top flow × min(flow share, √(p / p top)).
Losses: 30 % + 2 × air °C, kept to 7–35 % as in Davos; 6 points less for fan guns; plus 1.5 points per m/s above 2 m/s. The last two are our assumptions.
Wind limits, our assumption: fan guns drift above 6 m/s, stop above 10; lances drift above 4, stop above 7. Operators report trouble from gusts of about 9 m/s; lances are more sensitive. Drift = wind × flight time, 5 s for fans, 7 s for lances.
Water temperature: TechnoAlpin’s rule of thumb is that 4 °C colder water equals 1 °C colder wet bulb. The calculator counts from 2 °C water; the forecast tables do not use it.
Cooling towers: a tower cools water towards the wet bulb and never below it, so it works best on the same dry cold nights as the guns. TechnoAlpin gives 30–90 l/s of flow at 15–45 kW depending on the model. Enter the water temperature after the tower in the calculator.
Chance: normal spread around the forecast, 1 °C now plus .35 °C per day. MET Norway gives no spread for this area, so this is our assumption, not a model output.
Reference guns where the make is unknown: fan 640 l/min, lance 120 l/min.
Flow share by wet bulb, our fit
| −1.0° | 5 % |
|---|---|
| −2.0° | 13 % |
| −4.0° | 30 % |
| −7.0° | 62 % |
| −10.0° | 88 % |
| −12.0° | 100 % |
Density, kg/m³
| −2.0° | 500 |
|---|---|
| −4.0° | 470 |
| −7.0° | 430 |
| −10.0° | 400 |
| −15.0° | 370 |
Gun catalogue
| Gun | Type | Top flow, l/min | Maker’s snow, m³/h | Pressure, bar | Power, kW | Nozzles in use | Start |
|---|---|---|---|---|---|---|---|
| Demaclenko Titan 4.0 | Fan gun | 720 | 120 | 8–50 | 23 | 84 | -1° |
| Demaclenko Ventus 4.0 Blizzard | Fan gun | 540 | 90 | 8–50 | 20 | 64 | -1° |
| Demaclenko Evo 3.0 | Fan gun | 432 | 72 | 8–50 | 16,2 | 45 | -1° |
| TechnoAlpin TR10 | Fan gun | 757 · flow estimated | — | 8–40 | 23,3 | 24 | -1° |
| TechnoAlpin TR9 | Fan gun | 568 · flow estimated | — | 8–40 | 19,5 | 18 | -1° |
| Supersnow 900 Automatic | Fan gun | 645 | 105 | 8–40 | 22 | 120 | -1° |
| Supersnow 700 A SE | Fan gun | 480 | 80 | 8–40 | 17 | 90 | -1.5° |
| Supersnow 600 M | Fan gun | 480 | 78 | 8–40 | 18,5 | 90 | -1.5° |
| MND SUFAG Peak Plus | Fan gun | 640 | 96 | 8–40 | 26,5 | 310 | -0.5° |
| MND SUFAG Super Access | Fan gun | 560 | 81 | 8–40 | 23 | 300 | -0.7° |
| Экосистема ESG, 36 м³/ч | Fan gun | 600 | 90 | 8–16 | — | — | -2° |
| Supersnow VIRGA | Lance | 330 | 60 | 8–40 | 2,2 | 12 | -1.5° |
| TechnoAlpin V3ee | Lance | 120 | — | 8–40 | 2,2 | — | -2° |
| HKD Impulse | Lance | 303 | — | 13–40 | — | — | -2° |
TechnoAlpin does not publish top flow in these sources: 757 l/min comes from a SAM figure for the TF10, TR9 is scaled by nozzle count.
Questions
At what temperature do snow guns work?
Makers name a start from −0.5 to −2.5 °C wet bulb and air no warmer than +2 °C. In practice a gun works noticeably from −4 °C wet bulb, and by our estimate reaches top flow near −12 °C.
How much snow does one gun make per hour?
By our estimate a fan gun with a 640 l/min top flow gives about 20 m³ an hour at −4 °C wet bulb, 48 m³ at −7 °C and 95 m³ at −12 °C. Makers quote up to 72–120 m³ an hour for ideal conditions.
How much water does snowmaking use?
One cubic metre of water gives about two to two and a half of snow. TechnoAlpin counts about 1,000 m³ of water for a 30 cm base on a hectare.