Preparation of the Cross-Country courses for the 2022 Olympic Games

Many enthusiasts got to know the tough Cross-Country courses in Zhangjiakou during these last weeks. The elevation (between 5400 – 5650 feet), the cold temperatures (+5 to -5 Fahrenheit), the strong wind (20 – 30 miles per hour) and very slow snow (“sandpaper snow”) made the already challenging courses extraordinary hard.

The snow in itself was perhaps more durable and consistent than in any prior Games. Where blowing snow did not fill in the classical tracks, or during those calm days the snow proved to be amazingly strong and even around the whole course. After a day with perhaps a thousand skied laps in the stadium or in the test tracks the snow did hardly change. Problems with sugary or mealy snow, icy tracks and soft snow did not exist.

Groomers from both Norway, Canada and China formed our team

The about 6 miles long Cross-Country course consisted of more than 90% man-made snow that had been produced in November and December in around zero degrees Fahrenheit and with low humidity – almost perfect conditions. The water came from the local reservoir that had been filled up by the local creeks and natural springs throughout the rain season in August and September. Additionally, the temperatures were consistently way below freezing during January and February. A couple of snow storms added about 20 cm of new snow that was mixed into the existing 50 – 80 cm deep layer of man-made snow.

The actual base preparation of the Olympic courses took place the last week before the Games started. Both width and depth were checked and adjusted, banking/super-elevation of the corners were both increased and decreased, a ski-test area was built, the stadium flattened and safety fences and padding installed in a few critical locations.

All the necessary grooming equipment was in place. Two large and two smaller grooming machines were use for the main preparation both prior to and during the Games. The classic track setters had their own tillers in front, and all the combs were the Nordic kind (with smaller rills). The classical tracks were set with both the large machines (quad track setter) or the smaller (dual track setter). In addition, the venue has purchased several large utility type snowmobiles and grooming attachments that could be used for grooming close the competition times.

After the jury arrived at the Olympic venue, they decided the final details of the grooming during the competition period. This consisted mainly of deciding where the start and stop the classical tracks around the courses and in the stadium during the different formats. Due to the strong wind, the grooming to place usually in the morning, not too long ahead of the course opening for training, ski testing or warm-up.

2022 Olympic ski jumps ready

The amazing ski jumping hills built for the 2022 Olympic Games are now ready for the first Olympic jumpers. During the last few weeks the operations team has added a bit more artificial snow as well as received a bit from the sky. The final decorations are now taking place. The weather has been cold for several weeks, with almost -20 C now two days before the first competition. The hills are well protected; even with wind over 10 -12 meter per second at the nearby Cross-Country and Biathlon stadiums, there is less than 4 meter per second wind at the ski jump stadium.

New research: Indoor refrigeration system for snow production

The objective of this research was to investigate indoor snow production and the improvement of the current systems. In 2019, there were about 50 year-round indoor ski facilities worldwide (Skoblickaya and Sherement 2019). Despite this large number of indoor ski areas, there is little literature on the energy efficiency of indoor ski facilities, indoor snowmaking or the refrigeration systems used.

The reference system of this research work was the indoor ski hall “SNØ”, which is located near Oslo, Norway. In order to achieve good snow quality, the temperature in the ski hall must be lowered for the snow production. To reduce the energy consumption, a snow production system was designed and evaluated in which snow is produced in external towers. The basic idea of the external snow production towers is to keep the temperature of the hall constant without the need for cooling down the complete hall, while snow is produced.

External production towers and energy analysis

The designed snow production system consists of four external towers. The CO₂-based refrigeration system is centralized, see Figure 1. To facilitate the distribution of the snow, the production towers are placed at different locations around the main hall.

Figure 1: Refrigeration system. The grey area shows the part of the refrigeration system, which would
be needed for the external snow production.

The external snow production towers are designed with a height of 10 meters. This height is not enough for the drops to freeze completely until they reach the ground. In order to increase the time for the droplets to freeze, the towers must be operated with an air counterflow. This would need to be further investigated to also determine the energy consumption of these fans and add it to the overall energy balance.

The evaluation of the energy efficiency showed that about 44 928 kWh of electricity can be saved per year if the external snow production towers are used compared to the snow production in the hall. These 44 928 kWh correspond to about 0.7 % of the total energy consumption of the indoor ski hall.

A problem that occurs with the relatively small external snow production towers is the increase in humidity during snow production. This leads to a faster formation of frost on the evaporators, which has a negative effect on energy efficiency. An overview of defrosting methods is given in this work, but further research must be done.

Conclusion

This research work showed that the snow production in external towers is a possible way to reduce the energy consumption of indoor ski facilities. Further research is needed on a more detailed planning of the refrigeration system for the snow production towers and also on the defrosting method of the evaporators.

Authors: Susanne Lang

Year of publication: 2022

Reference: Skoblickaya, Yulia; Sherement, Anastasia (2019). The architectural and planning organization of the closed complexes for winter sports. Journal of Environmental Management and Tourism 10 (5) 2019.

Preparation of the 2022 Olympic Games Ski Jumps

The 2022 Olympic Ski Jumps will be introduced to the World during the Games in February this year. The TV viewers will guaranteed be impressed by the grandiose facilities surrounding the jumps themselves, especially the football-field large futuristic looking building above the start houses.

Getting the jumps ready for the competitions is however like any other international year-around ski jump and includes lots of manual work and effort. Here is a peak into the steps and challenges that the operations team faced these last couple of months.

Step 1: Build one-of-a-kind ski jumps that meet all the FIS homologation requirements (not as easy as it sounds).

Step 2: Clean and wash the in-run tarps and in-run track before the snow season starts

Step 3: Install snow-nets before the first snow comes (if not, remove all the snow from the landing hill). Hint: The Olympic venue team experienced the results of being late with the installation of the snow nets (see photos)

Step 4: Make snow in the stadium/outrun and flatten the outrun, then create wet snow in the radius of the hill and bit by bit up the hill as far as the snow-fans can be moved

Step 5: Use the snowcat to push snow up the landing hill (from the bottom), creating a solid foundation to rest the snow on the landing hill on, and avoid the chance of any snow sliding down

Step 6: Make a bit of snow at the knoll (the flat top area) and connect with the landing hill snow

Step 7: If there are problems with loose (sugar) snow that makes the winch cat spin, know what to do. Hint: water the snow just ahead of the winch cat to create more friction (see photos), then let it freeze for a few hours or overnight.

Step 8: Measure the snow depth across the landing hills, and move/push snow around to create an even surface across the landing hill according to the required profile/depth of snow

Step 9: Compress/boot-pack and smooth out the snow along the sideboards (the whole width of the hill must be equally firm to guarantee a safe landing area)

Step 9: Build the inrun track

Step 10: Build the perimeter fence around the outrun

Step 11: Decorate the hill for the test event

Step 12: Learn from the test event and fine-tune the venue before the Olympic Games starts (this work is still ongoing as of today January 2^nd). Look happy anyhow!

PTG joins Snow for the Future

Norwegian supplier of sustainable temperature and energy solutions PTG is joining research project Snow for the Future.

“We’re thrilled to become a part of the team, says CEO of PTG, Terje Arnesen. For us, participating in research at such an early phase is a great way to develop competence. The ultimate goal is to create innovations that have the potential to become new products.”

Snow for the Future is an international joint project to develop climate-friendly and cost-efficient snowmaking technology for ski resorts and winter sports facilities. The project was launched in 2017 and is scheduled to continue until next year.

PTG employees standing in front of a gigantic heat pump at Salmon Evolution in Harøy, Romsdal

2022 Olympic Cross-Country venue ready for snowmaking

The brand new 2022 Olympic Cross-Country venue is located outside the city of Zhangjiakou a couple of hours north of Beijing (with the Ski Jump and Biathlon venues located adjacent). The Cross-Country courses are built at an elevation between 1693 – 1721 meters. The venue has gone through a 5-year’s planning and construction process, and are now is its final stages of preparation for the Games in February.

The weather in the area is now turning cold, and the snowmaking system is ready to be turned on. The traditional snowmaking system consists of a large 200 000 m3 reservoir, an elaborate pump house and water system and over 70 hydrants around the courses. The system is fully automated with the newest technology where the consistency of the snow and the control of each snow-gun can be set from a central PC. Due to the dry climate in the winter months and minimum natural snow, the venue is totally dependent on the snowmaking system for skiing (the rain typically comes in August and September, and fills the reservoir).

With twenty snow-guns available it is still a lot of work for the operational staff to move the snow-guns around the 10 km course system – from section to section. It will take 5 – 6 weeks to lay the snow down, push the snow-piles out and groom the courses ready for skiing. With the expected consistently cold temperatures in November and December the operations can take place 24 hours a day in three shifts.

The venue’s grooming equipment consists of two Prinoth Bisons and two Prinoth Huskys (with respective quad- and dual track pans) machines, as well as snowmobiles with miscellaneous grooming attachments. The biathlon and Ski Jump venues have an equivalent machine park.

The first international use of the venue will take place during the December 2 – 5^th Nordic Combined Continental Cup competitions, although last year the venue was used for a week of domestic competitions for the Chinese Cross-Country teams.

The Cross-Country courses are designed in cooperation with the Olympic Cross-Country broadcast director, and should present the sport in an optimal way. The terrain originally consisted of open fields with the lower parts used for cabbage production. In the last two years 10’s of thousands of trees have been planted to give better wind protection for the courses and provide a more varied landscape.

Last week, the courses were certified (homologated) by the International Ski Federation (FIS). They are demanding as required for Olympic competitions, but without super-long climbs. Undulating sections and a few technical downhills are included, and should be well liked by all skiers (see profile and plan of Olympic 7.5 km course below) .

During the Games, a few of the Cross-Country and all of the Nordic Combined competitions will take place during the evening.

Snow storage enables early opening of Cross-Country skiing

Several Norwegian Cross-Country venues have already completed or are in the process of distributing snow from their summer storage. Here is a list of venues that have gained the competency and resources to store snow over the summer months, and the dates for when skiing will open (the information is taken from langrenn.com).

Natrudstilen (ca. 6 km): October 15th
Beitostølen (ca. 5 km): October 29th
Dombås(ca 3.5 km): October 29th
Trysil (ca. 6.5 km): October 30th
Furutangen (ca. 2.5 km): November 6th
Granåsen (ca. 3.5 km): ca. December 1st
Birkebeineren stadium: for World Cup opening December 3rd

Oberstdorf’s excellent snow handling during the World Championship

The February 23^rd – March 7^th 2021 Nordic Ski World Championships in Oberstdorf observed unprecedented warm temperatures with the potential for disastrous and unfair snow conditions – the Organizing Committee (OC) solved the challenges in an excellent way. Here are the highlights of what they did…

The situation:

During the Championship it was mostly sunny and, especially in the beginning, very warm for the season
Only 3 days were cloudy without any sunshine, and 4 days brought precipitation of more than 1 mm
On February 22nd Oberstdorf recorded a maximum temperature of 19.3 Celsius, a new record for this time of the year
Due to the cold air pooling in the valley bottom, every night had light frost between 0 to -6.6 deg C.
The sunny days brought very different radiation, depending on the shade, and resulted in a big difference in temperature along the courses even at the same elevation
On calm days it was also observed a big difference in the temperature relative to the elevation of the courses; up to14 degree temperature difference was measured between the valley bottom and the highest point of the course
On most days, the humidity in the snow would change from about 25-30 % in the morning to over 75 – 90 % in the afternoon
It was observed a loss of approx. 30cm of artificial snow in the period February 18^th to March 7^th

OC experience – Cross-Country courses

The course preparation was difficult due to extremely variable snow conditions during the Championship. The course sections in the shady areas were hard all over, while the areas being exposed to the sun would soften extremely fast around midday, mostly during competition times.

In order to guarantee optimal working conditions for the athletes, the following measures were implemented:

Earlier start times for Qualification race and Sprint prologue
Reduction of training times and course opening times or complete cancellation of training times
Closure of partial areas for training and warm-up
Partial non-preparation of extremely stressed sub-areas
Producing a rough surface with the snowcats without using the tiller after sunset
Individual, optimal timing of the snow preparation was essential for the snow quality; snow should only be slightly wet and grooming starting just before freezing
The areas in the shady parts were prepared first, with a very slow driving speed
In areas with high exposure to sunlight, the time of preparation plays a significant role; too early can lead to a layer of ice on the surface
Maximum resting time after preparation for sintering is crucial
Sintering is difficult with large and round-grained old snow; slow travel speed of the grooming machine with simultaneous high milling speed and closed cutter
Areas in the stadium were only prepared in forward/backward driving mode, reducing driving in curves to a minimum in wet snow conditions
The new snowfall was worked into the existing coarse-grained and round-grained old snow by heavy milling/tilling to improve the snow structure

Snow hardening/salting

German pretzel salt was used exclusively (dosage: 12 -15gr/m²). The application of the salt was generally done in the morning. It was known that high snow humidity is necessary to dissolve the salt. The salt worked very fast, after spreading it took only approx. 20-30 min until the snow had hardened. It was observed that with larger grain size the snow hardening has a deeper effect and lasts longer.

Application:

Daily salting tests in agreement with FIS staff and jury
Test areas in the stadium, sun exposed areas and ski test area
Control of the effectiveness was done every half hour
Salting of the stadium in the early morning was often necessary in order to be able to set up the stadium with volunteers without destroying the prepared surfaces
Spreading was done by experienced staff (Alpine WC Ofterschwang, TDS, City Sprint China)
Numerous salt depots on the course at optimal strategic points
Detailed personnel schedules for the application of the salt. The application of salt was done by hand, with professional golf course fertilizer spreaders and with electric spreaders attached to skidoo or grooming machines
Less is more -better to start with low dosage to work on the surface, reworking of the surfaces according to the needs and effectiveness of the snow hardener
Course areas that were not used during competitions were also salted to create equal conditions

Ski Jump experience and preparation

Due to the warm weather conditions, large round snow grains formed without any connection (sometimes called “sugar snow”).

A reconstruction of the outrun area HS 106 to HS 137 took place on 28.02/01.03.

During the competitions on the normal hill/HS 106, the landing zone of the HS 137 was not prepared.

Use of Norwegian/Fire brigade sprinklers with several 1000 litres of water made it possible to prepare the landing zone.

Before the competitions, the volunteers additionally worked with pretzel salt.

Granåsen Sportspark – a unique snow venue

The Granåsen Sportspark in Trondheim, Norway, home to the 1997 and the upcoming 2025 Nordic Ski World Championship, has become one of the most versatile and modern Nordic venues in the World in terms of how it delivers and guarantees snow to its users. The venue is an operational “laboratory” for those wanting to learn about snow production and snow storage, such as the pros and cons of the different systems, the operational benefits of certain production units, and the cost-benefit of one system over the other.

The venue layout

The venue consists of four different parts; the original Cross-Country stadium and 3 km West area (which is covered with snow from the snow storage pile), the upgraded 4 km East area (where snow is produced by fan-guns), the newly constructed 1 km Litjåsen (“Little Ridge”, where snow is produced using snow-lances) and the ski jumps (also using snow-lances).

The venue’s snow production system was upgraded in 2018 – 2020, which also included installing an automated system that can be controlled from a PC or a mobile phone. The valve-pits and hydrants are place approximatelly 50 meters apart (closer together for snow lances than for the fan guns).

The capacity of the different production units varies quite dramatically (tower guns make more snow per hour than the fan guns, which make more snow than the lances), also with the temperature/wetbulb. The capacity doubles when the temperature drops from -3 Celcius to -7 Celsius.

Operational learnings

The operational learnings can be summarized as following:

Fan guns are flexibly moved between the valve pits/hydrants by the grooming machines, and require frequent staff resources during operations to adjust the units according to the wind direction and make sure they do not “bury” themselves. The units can be started manually or automatically. Fan-gun systems (water pipes only) are less expensive to construct/install than systems for snow lances (both water and air pipes), but are more labor intensive/costly to operate. Fan guns produce more snow but also more noice than snow lances.

Snow lances are permanently installed and produce snow around the entire section of course. They are efficiently (with minor setup) started automatically according to the system settings. Some minor staff resources are needed to adjust the lances according to the wind direction. Snow lances are easier and faster to operate during short periods of cold temperatures. Snow lances require less maintenance than fan guns and are overall less expensive (less staff resources) and easier to operate.

Stored snow is transported out onto a section of the Cross-Country courses and the stadium typically in mid-November. An initial snow pile of 25 000 cubic meter is reduced to 20 000 m3 due to melting over the summer. The snow storage pile ensures a guaranteed opening date for the venue, but is expensive in terms of labor, electricity (for snow production), machine cost (for covering/uncovering the pile, and for distributing the snow), and the saw dust cover material (which is not re-used).

Summary and advice

A cold water source with a bit of humus/peat moss is important
Intitial higher investments may result in large operational savings later
Noice from prodution units and grooming machines must be considered near populated areas
Breathable cover material, sufficient storage area, clean transport roads/paths and smart distribution plans are important for successful snow storage
Staff education, competency, transfer of knowledge and risk-analyses are important factors for long-term operations

New research: Temperature independent snow production systems can be significantly improved

Snow for the future research project shows that there are large differences between the different temperature independent snowmaking systems, and that they all can be significantly improved. Read more here.

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