This is how we produce snow in Hafjell

HAFJELL, At most under optimal conditions, we can produce five truckloads per minute of snow, but there are many factors that play a role in getting snow production started. 

The main ingredients for producing snow are compressed air and high-pressure water in large quantities. In Hafjell we use three types of snow cannons, and common to them all is that water under very high pressure is forced through a number of nozzles that atomize the water. In some of these nozzles, the water is mixed with compressed air to start the freezing process. We have two types of fan cannons and a lance cannon. We will explain these a little further down.

For there to be snow, we need an effective temperature that is below -2.5. The higher the humidity, the more cold is needed to be able to produce. The main rule is that you need between -5 and -10 degrees for 7 days to be able to open (depending on the length and width of the ground).

Fan cannon

These can be fixed or mobile and are transported around the facility with preparation machines. We have several of these in Hafjell, and some can blow 70 meters into the ground. For example, one of these fan guns is called the T40 (as shown in the picture). The same for all of them is that they have a large fan at the rear that means that the water droplets from the nozzles at the front of the cannon are blown 20-40 meters into the ground. The time the water droplets, and eventually the snow crystals, are in the air is crucial for how much can be produced. 

Lance cannons

We also have something called lance cannons. These are long lances of 6 meters that are fixed along the trails.

The lance cannons are of the V3 type. This type of cannon is used in most of the trails in the northern part of the facility. On these, there is water and air pressure that throws the water droplets/snow crystals into the ground. These guns have less capacity and range than a fan gun, so the distance between each lance gun is shorter, and you need about three lance guns to produce the same amount of snow as one large fan gun.

Optimal conditions

The best conditions for snow production are -10 degrees and clear weather that often results in dry air. The amount of snow depends on temperature, so even if the snow cannons are running at full speed in the mountains, the number of cubic meters of snow will vary greatly depending on how many effective degrees of cold we have.

The largest fan guns can produce up to 100 m3 of snow per hour under optimal conditions. At marginal temperature conditions, the same cannon will be able to produce down to 5-10 m3 per hour.

In most of the main routes in Hafjell, the snow cannons are permanently mounted along the sides of the trails. These guns have a central control system and can produce snow "automatically" when temperature conditions allow. This makes snowmaking more efficient, and we get a more even snow quality even if the temperature varies during the day. In 2015, in connection with the construction of the National Facility in Hafjell, snow production was significantly upgraded with this automatic system. The amount of water is thus adjusted according to the temperature outside, so that the overall quality is more even and better.

In total, snow production covers 90% of all routes in Hafjell Alpine Center.

Water capacity

Our main source of water is Reinsvatn, a lake located between Nevelfjell and Reinsfjell in Øyerfjellet, and is approx. 3.8 square kilometers. Water is also collected from Lake Moksjøen, which is located a little further north. Previously, water was also collected from Gudbrandsdalslågen, but this was removed when the water system was built from Reinsvatn. The reason for changing the main source was both because of capacity, but also because of environmental considerations.

When the snow system is running at full speed with us , we can produce up to 60 cubic meters of snow per minute. That equates to a total of five full truckloads!

Then there are many who wonder why not all the cannons go off when it is cold. It is the case that we do not have enough water to run all guns equally at low temperatures. Therefore, priority is given to the slopes and trails that will open first, typically at the top of the mountain and the main routes. Production is then expanded to the rest of the trail network, and normally we also get good help from the natural snow when we get to the end of November – December.

Under normal weather conditions, all main trails, children's areas and terrain parks are ready for Christmas.