Oberstdorf’s excellent snow handling during the World Championship

The February 23rd – March 7th 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 18th to March 7th

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.

Prinoth releasing full electric as well as hydrogen powered grooming machines

The Italian based grooming machine company recently released its much anticipated fully electric groomer Husky eMOTION with a 190 kWh battery capably of 3 hours of runtime with a torque of 1140 Nm.

At the same time, the company also released its hydrogen powered machine Leitwolf h2MOTION. The hydrogen powered machine is capable of 544HP and 2300Nm of torque with a 4 hour run time.

See our partner FIS web site for further information.

Will using excess heat for snowproduction save the ski season in the future?

Climate changes will lead to warmer temperatures and less natural snow.  A likely consequence is that it will become more difficult to provide good conditions for snow sports.  The ski season may even disappear in many typical “snow villages”.  Since the traditional snow production method using snow lances or fan-guns require temperature below zero degrees Celsius, many locations, especially at low elevation, may not be able to use this method in the future.

Temperature indepedent snow production

One alternative is to use technologies that can produce snow in warm temperatures, so called temperature independent snow production.  Today there are several providers of this technology, and it is used in several places around the World.  The systems are costly, and require that the snow is distributed since the production takes places in a central location.  Compared with traditional snow production, the technology demands up to 50 times more energy, which leads to high electric bills.

One solution for reducing the operational costs is to replace the electricity with heat as the energy source by using refrigeration technology driven by heat (for example absorption refrigerators).  To produce snow using heat requires temperatures of around 90 – 100°C.  Compared to using electricity, heat-driven cooling is relatively inefficient, since large parts of the heat can not be utilized.  To be economical, such a solution is therefore dependent on being able to use cheap or free excess heat.  This will also contribute to reducing the environmental footprint compared to snow making using electricity.

Potential heat sources

In Norway, studies have shown that one can find considerable amount of unused excess heat, especially in industry and waste incineration.  In the industry there is potentially up to 10 TWh of available heat at the right temperature range, while for incineration about 1 TWh is not utilized for district heating due to low demand in the summer.  Making use of heat from these sources is however not without challenges.  The low temperature of the district heating in the summer makes it difficult to use for snow production, and external use of excess heat from the industry is demanding and not common.  Both cases will require relatively expensive heat exchange equipment for both user and provider, as well as pipes for transporting the heat between the two.

  • District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements.

Co-location of venues and heat sources

Snow production using heat as the energy source for snow production, it is advantageous that the heat source and the ski location is within a short distance; neither heat nor snow can be transported efficiently over long distances.  In Norway, the co-location of winter sport venues for Cross-Country biathlon, ski jumping and alpine, and potential heat sources has been mapped.  This shows that 76 out of 168 mapped venues are located in a municipality with district heating or available excess heat from industry. For many of these venues increased snow production would lead to increase skiing since they are located in densely populated areas or are already popular ski destination venues.

Based on calculations with Granåsen, Trondheim as model example, an annual consumption of 1,5 GWh for snow production would contribute to lengthening the ski season with more than 1 month by being able to snow cover the stadium, 3 km of courses and the ski jumps.  At the same time, the calculations showed that different factors can significantly alter the energy requirements.  The model calculations will therefore be unique for each venue.

Further work

The text above is a summary of a research project by SINTEF (author: Ole Marius Moen – ole.moen@sintef.no).  The project can be categorized as a mapping task, where the focus has been to find:

  • Which heat-driven cooling technologies exist and can be used for snow production?
  • How much energy will heat-driven snow production require?
  • What are the potential sources of heat?
  • Which winter sport venues (in Norway) can potentially use this type of snow production technology?

It is suggested that further research focuses on large venues with existing nearby district heating.  Techno-economic analyses to demonstrate each individual venue’s potential may tell us if heat-driven snow production is a practical, economical and sustainable solution for future winter sports.

  • Technoeconomic assessment or Technoeconomic analysis (abbreviated TEA) is a methodology framework to analyze the technical and economic performance of a process, product or service. TEA normally combines process modeling, engineering design and economic evaluation.

China’s Olympic and Paralympic venue in operational mode

The new 2022 Olympic and Paralympic venue for ski-jumping, biathlon and Cross-Country is producing snow as if the Olympics and Paralympics were taking place this year.  Although the international World Cup test events are cancelled due to Covid-19, and no international athletes are able to test the courses, shooting range and jumping hills, the Olympic and Paralympic organizer and venue owner are working towards a competition ready venue by the end of this year.

The brand new and complicated snow production system must be tested, and the operational staff must gain experience in making and grooming the snow in the most efficient way.

The three stadiums for jumping, biathlon and Cross-Country are within a 2 km half-circle, and the traditional snow production system is operated centrally with a capacity of 900 m3 water per hour.  A 200 000 m3 reservoir is full due to the heavy rain this summer, and 200 hydrants are strategically placed around the courses and jumping hills such that approximately 50 fan-guns and snow-lances can be moved to produce snow on two ski-jumps and about 20 km of courses.

Due to the cold and dry weather conditions (the venue is at ca. 1600 m/5300 ft above sea level) the snow production is running 24 hours a day.

Photo: Wei Qinghua
Photo: Wei Qinghua
Photo: Wei Qinghua

Lysgårdsbakken in Lillehammer ready for jumping

Cold temperatures and traditional snowmaking got the jumping hill ready for this weekend’s competitions, but both stored snow and a new way of distributing the snow were used and tried along the way.

Photo: Marit Gjerland
Photo: Marit Gjerland

The Normal Hill (K90) was covered with snow from last summer’s storage (just up the hill near the Cross-Country stadium).  In November, a new way of distributing (transporting) snow was also tested out on the ski jump (see photo and check out norsnowing.com).

Photo: norsnowing.com

Granåsen, World Championship venue for 2025, is testing it’s new snow systems

Granåsen arena on the outskirts of Trondheim, Norway, is this week distributing its snow-storage onto the competition courses. Those courses are planned to be used for the 2025 Nordic World Skiing Championship, but more importantly right now, for the January Norwegian National Championship.

Loading up trucks at the snow-storage site (Photo: Helge Johansen)
Snow on the courses prior to grooming (Photo: Helge Johansen)

Granåsen has stored snow for several summers now (about 15 000 cubic meters), but has also upgraded its snowmaking systems considerably the last two years. Their conventional snowmaking system is now fully automatic, uses high-capacity tower-guns in the stadium, efficient fan-guns around the main competition courses above the stadium (where temperatures are often marginal) and with snow-lances around their newest 1.5 km course below the stadium (where the temperatures are often colder than the rest of the venue).

New tower-guns in the stadium (Photo: Helge Johansen)
Snow lances along the new courses (Photo: Helge Johansen)

French ski resorts turn to hydrogen in drive for CO2-free snow

From Bloomberg Green (bloomberg.com/green).

France’s 250 ski resorts will switch to hydrogen-powered snow-grooming machines as they seek to make good on a pledge to cut direct CO2 emissions to zero by 2037.

Diesel-fueled grooming machines produce 94% of the carbon emitted by French ski resorts, with the running of lifts and snow-making equipment accounting for the rest, Alexandre Maulin, the head of industry group Domaines Skiables de France, said at a press conference on Friday.

The ski lobby is working with France’s Alternative Energies & Atomic Energy Commission and the three main suppliers of grooming machines — Germany’s Kaessbohrer Gelaendefahrzeug AG, Italy’s Prinoth SpA and local producer CM Dupon — and expects the first hydrogen-powered snow groomer on the market in five years.

“Yes, we are a source of pollution, the ski area, we’re going to deal with it,” Maulin said. “The first work will be to help with production of hydrogen-powered snow groomers. It’s a priority for all the manufacturers.”

France’s largest ski stations typically replace their snow groomers every five seasons and smaller ones every 10 years, Maulin said. So the entire French fleet of grooming machines could be switched to hydrogen over a decade, after a period of testing and working out bugs, he said.

The tracked machines, weighing over 10 tons, on average cost 400,000 euros ($469,000) a piece, according to Domaines Skiables de France. Manufacturers will recuperate R&D costs for hydrogen power in the price of their snow groomers, Maulin said.

  • French ski resorts invested an average 379 million euros a year between 2016 and 2019, with 10% of that spending on snow-grooming machinery, according to Domaines Skiables de France
  • Snow-grooming machines accounts for 94% of French ski station’s direct emissions, ski lifts 4% and snow-making equipment 2%
  • The French Alpine resort of La Plagne, the world’s biggest by number of skier visits, has 30 snow groomers to maintain its 225 kilometers of runs
  • France has introduced a 7 billion-euro plan to use hydrogen in industrial processes and transport to cut its carbon dioxide output by 6 million tons by 2030
Electric grooming machine (Photo: Kaessbohrer AG)

Solden World Cup

Solden opens the alpine World Cup in great conditions by using water injection.

Twenty-six men and two converted Pisten Bullys with one spray bar each with a width of 14 meter were used. The water was injected at a distance of 10 cm at 30 bar (the water will go to a depth of 30 – 40 cm).
The result is a slope that creates fair conditions through the entire competition.

Photo: Solden World Cup
Photo: Solden World Cup