Snow production– findings from IBU’s SIEPPUR project

For the last couple of decades, snow production has been able to compensate for the decrease in natural snow that has been observed in many places around the World.  Depending on the availability of water, the cost of snow production and the actual rise in temperature due to climate change, this compensation may continue for a long time in certain regions.

Produced snow is sometimes called technical snow since the snow provides a resistant surface that is denser and grippier than natural snow, suiting snow competitions well.  Compared to natural snow, the grains are smaller, will sinter (bind together) faster and become much more resistant to loss from warm temperatures and rain.

In terms of productivity of conventional snow production, it is found that 1 cubic meter of water will in optimal conditions produce up to 2.5 cubic meters of snow.  Usually, it is less than this due to vaporization and wind, as well as loss from water droplets that are not frozen when they land on the ground (especially in marginal temperatures). 

Fan guns have a larger production capacity than snow lances while snow lances are more energy efficient.  In terms of energy efficiency, they are both superior compared to temperature independent snow production systems (i.e. snow factories).

The design of the snow production system and the operational models at the researched IBU venues varied quite a lot.  There is a mix of distributed and centralized snow making operations, as well as several venues using both snow storage and snow production systems.  Each operational model has its pros and cons.

Snow storage – findings from IBU’s SIEPPUR project

Storing and preserving snow over the summer will enable on-schedule snow reliability – a venue can open for skiing on a pre-announced date.  The key question is however how to lose the minimum amount of snow over the warm summer months.  The main factors that cause snow melt are:

  • Air temperature/sun (shortwave radiation) and wind speed
  • The efficiency of the cover material; the cover must:
    • insulate (and have no gaps)
    • have the ability to reflect the sunlight
    • absorb water
  • The size and shape of the snow pile
    • should be 7000 m3 or more
    • A too large snow pile will form ice layers at the bottom
    • It should be shaped like a half-cylinder

SIEPPUR’s scientific research has identified the following factors to improve snow storage efficiency:  

  • a closed cover prevents direct (convective) heat transfer from the air to the snow 
  • the thicker the cover the less heat is transferred ​down into the snow
  • the lower the heat conductivity of the cover, the less heat is transferred 
  • materials with a high heat storage capacity absorb heat during the day and release it back at night​ 
  • materials that absorb water release heat when the water evaporates (and will therefore cool off the snow)
  • highly reflective surfaces prevent energy input by shortwave radiation (cover should be as light color as possible and resistant to contamination)​ 
  • the cover should be able to emit heat overnight (called longwave radiation), and thereby cool down. In other words, heat resulting from the absorption of incoming shortwave radiation (from the sun) is emitted as longwave radiation at night

Environmental impact and cost

The research has found that to increase efficiency, reduce cost and environmental impact​ of snow storage, the following practical considerations are key: 

  1. Planning​ 
  2. Structural measures​ 
  3. Snow making / pile size & shape​ 
  4. Applying the cover 
  5. Removing the cover​ 
  6. Spreading and preparing​ the snow
  7. Storing the cover or cover material

Some practical tips:

  • Ideally, produce the snow at optimal temperatures​ during the winter (produced snow is more durable than natural snow)
  • Store the right amount​ of snow; the snow storage pile should be at least 7000 m3 to avoid extensive loss (the ratio of volume to surface area is important)
  • Use the right cover; sawdust/wood-chips will preserve the snow better (less than 20% loss) than other materials (which lose more than 30%), but may be more labor intensive and costly
  • Use the right amount/thickness for the cover material; at least 30 cm is needed​​ when using sawdust or woodchips
  • Ensure smart design of the venues​: usually more than one pile at different locations is beneficial to reduce the traveling distance, even though there is some extra work and cost with two or more piles
  • Reduce the distance between storage and the ski tracks
  • Prepare a distribution plan: snow transportation drives costs ​and energy consumption
  • Don’t put out the snow too early so that it melts 
  • Use renewable energy​ 
  • Identify the optimal snow cover ​that is:  no microplastics, easy to install with minimal work, small snow losses, long-lasting, low price

IBU’s exiting new snow management project

The project, named SIEPPUR after the Sami word for deep snow, aims to identify, develop and promote sustainable practices in snow management from production, storage, transport, grooming to handling.

The European Union Erasmus + Funded 3-year project started already in late 2022, and has this summer and fall delivered detailed findings and summaries.  The main partners/contributors and research expertise within the project comes from the Swiss WSL Institute for Snow and Avalanche Research (SLF) and the Swedish innovation hub for sports & outdoors, Peak63.

This fall SIEPPUR is hosting three webinars to highlight their key findings. The findings are based on assessing the snow management practices of many highly diverse biathlon venues – regarding ownership, operations and environmental regulations – from around Europe ranging from large, top modern World Cup ski venues to smaller, less developed, or developing ski areas. The venues were surveyed, visited and data collected. The detailed assessments consist of quantifying the water and energy used for snow making, grooming and snow storage and identifying best practices as well how venues deal with different constraints. e.g., from a warm climate, nature conservancy, or governance practices.

The 10 venues collected and shared data with the project, such as:

• Snow production:  the number of snow lances, snow guns, the volume of snow produced, the hours, the volume of water and kWh of electricity used

• Snow storage and grooming:  machinery details (type of vehicle, number, weight, power (kW), type of fuel), hours and manpower for the storage procedure including: pile shaping, covering and removing the cover, snow spreading and preparing (including grooming work)

• Fuel consumption in different snow types:  how different types of snow dominate the upper 10 cm of the skiing surface and whether it’s new, winter, machine-made, spring or storage snow and how this affects the fuel consumption in grooming

The results of the research are presented in several documents and summaries on the SIEPPUR web site – https://sustainablesnow.sport/

Snowcompetency.com will highlight the research findings in upcoming articles.

Canmore World Cup venue opens for skiing on October 19

The Canmore Nordic Centre opened its “Frozen Thunder” Cross-Country and Biathlon courses on October 19th this year.  In its 14th year of snow storage operations, it was able to store and keep more snow than ever before and will this year offer about 4 km of courses from the snow they produced last winter.

Canmore loses less percentage snow from their snow storage than any other venue in the World – 15% loss (or less) is fairly common, which is almost 100% better than many other venues.  The advantage in Canmore is the high elevation (1400 meter) with cold nights, dry climate, and smartly designed storage locations (they now have two locations).  The venue uses sawdust for cover material, and feels that this is better than woodchips or other synthetic cover materials.

Canmore is perhaps also the only venue in the World that recovers the cost of the snow storage expenses.  Due to grants from both the National and Provincial Cross-Country and Biathlon organizations, in-kind snowmaking from the venue operator, sponsors, as well as income from users’ ski passes the snow storage operational cost of approximately 150,000 EURO is covered.

Canmore says the benefit of snow storage is:

  • Guaranteed early season training for the National Team and the regional clubs
  • Event Insurance – many early season local events would be cancelled without snow storage
  • Guaranteed pre-World Cup selection races (most other venues struggle with snow in November)
  • Potential revenue (some years income surpasses expenses)

More efficient snowmaking technique being tested in Spain

The Barcelona Institute of Materials Science (ICMAB-CSIC) and the Tourist Agency of Catalonia have together with Techno-Alpine started the 3-year project Snow Laboratory to test whether a new kind of production technique can increase snowmaking efficiency.

According to the research manager, Albert Verdaguer, the new production technique is more similar to what happens in nature when snow is formed. Snow or ice nucleates when water droplets react with particles in the atmosphere, such as aerosols or dust, causing them to freeze more easily. A couple of years ago, Verdaguer read a research paper that found that one mineral — feldspar — was particularly effective at this process and could trigger freezing of water droplets at temperatures close to zero degrees.

It is this mineral that is now mixed into the water that is sent to the snow fans or snow lances in the La Molina ski resort in the Pyrenees. During laboratory tests, Verdaguer and his group found that the technique reduced energy costs by about 30% and was able to produce snow at temperatures around 1 to 1.5 degrees higher than traditional methods. They were also able to get a better “conversion ratio”, i.e. more snow coming out of the guns in proportion to the amount of water going in.

Difficult snow conditions for biathlon in Oberhof

Even one of the world’s most experienced World Cup organizers can struggle to provide good snow conditions.  World Championship and World Cup organiser Oberhof received complaints about pebbles and dirty snow on their courses when the biathlon venue opened for training the day ahead of the first scheduled World Cup competition this past week (4-7 January).

The weather in Germany has been completely opposite from the snowy and cold weather in Norway in recent days, and has instead had many days of mild weather, rain, fog and wind.  The organizer therefore had to bring in stored snow, and pebbles and dirty snow became an issue for both skiers and wax technicians.  We have also seen pebbles on race courses in Norway, and several volunteers have had the experience of walking around the courses with spoon in hand to pick up sharp things that ruin the athletes’ skis.

It is especially the combination of a too thin layer of snow on the courses and rain with subsequent high humidity that often creates high melting.  If the thickness of the snow on the course is about 40 cm or more, rainy weather is not the biggest problem as long as the humidity is low enough for evaporation to occur.  Evaporation (either during the day or at night) gives off heat so that the snow layer left on the course freezes over.  If, on the other hand, the humidity is close to 100% (as it is when there is fog) the snow layer will not freeze at all (and will continue to melt).  Even salting will not harden the snow when the humidity is 100%.

Heat from the ground can also eat away at the snow, especially where drainage is not optimal or if there has been no frost. To reduce heat from the ground, insulation mats can, prior to the winter season,  be laid down below 10 – 20 cm of sand or similar.  This has been done in connection with new roller ski courses in Finland (see https://www.snowsecure.com/en/storing-snow-for-xc-skiing).

When snow has to be transported from storage, it is of course important that the snow does not include pebbles and the like.  This is avoided if the snow storage pile is built on clean asphalt, and that the machines and vehicles are washed before use and do not pick up dirt on the roads.  In Granåsen, Trondheim, the stored snow is first transported to and temporarily stored on the paved stadium, where separate and “clean” vehicles transport the snow from the stadium and out along the roller ski slopes.

Oberhof has access to several snow deposits, and has previously also reused the snow from the World Team Challenge at the Schalke/Veltins-Arena football stadium held between Christmas and New Years.

Oberhof is one of the world’s best year-around venues for cross-country skiing and biathlon, with an impressive snow tunnel (see Thuringia Skisport-HALLE) where the temperature can be adjusted so that grooming and the snow is perfect every week regardless of the weather conditions outside.

Challenges with preparation in advance of Ski Jump 4-hill Tournament

Of all the snow venues, ski jumps are perhaps the most challenging to prepare, especially if plastic (for summer jumping) is installed on the landing hill.  The organizers of this year’s 4-hill Tournament really got a challenge in their lap when an avalanche happened on the famous Paul Ausserleitner hill in Bischofshofen just before Christmas.

Without special measures, it is almost impossible to get the snow to lie firm on a plastic ski jump landing hill with steepness of well over 35 degrees.  A snow net is therefore installed from the take-off down the landing hill before the snow is produced or brought from snow storage.  Natural snow is almost never used anymore at World Cup ski jump hills (not as durable and compact as man-made snow).

Installing snow net at 2022 Olympic venue

It’s quite a task to build up a safe snow-base throughout the landing hill.  This is done in the best way by starting at the very bottom of the hill and then “building stone by stone” right up to the knoll and take-off.  Read more about this here.

Base grooming at Trondheim, Norway

In Bischofshofen, both the snow net and the snow avalanched to the bottom of the hill.  This happened after a snowstorm followed by rain.  Avalanches can happen if too much snow is produced and prepped higher up in the landing hill without 100 percent anchoring from the bottom up.  If the snow net is not optimally attached, anchored and “frozen” into the ground (spraying with water in the evening and letting it “freeze” overnight), it is sometimes unable to withstand the gravity of wet snow.

As the Dagbladet newspaper writes, Bischofshofen borrowed a new snow net from Klingenthal and in an impressive way prepared the hill – again – just in time for the Tournament to start!

Trondheim World Championship test event with challenging grooming conditions

The Cross-Country World Cup event earlier in December (December 15-17) offered some of the most challenging weather forecasts and weather conditions.  Even with this, it was three very nice days of competition.

Here’s a little bit about the challenges the organizer had to deal with.

Granåsen is operated by Trondheim Municipality.  When there are sporting events, the Municipality’s operations department coordinates the trail preparation together with the event organizer’s Chief of Course.  During the biggest events, the race jury is also involved in the decision-making process regarding methods and timing of preparation.  Through the major events of recent years, Trondheim municipality has proven itself as a very good partner and has built up great knowledge and experience in preparation as well as a large equipment pool.

DAY 1 – Friday (Sprint skating):

Two days before the World Cup event, the weather forecast completely turned from showing -10 -15 degrees and fine weather for two months, to mild weather and snow the night before and during the first race day.  Would it be necessary to prepare the course between the sprint prologue and each heat? What equipment should be use to prepared the snow with?

Since the jury decided that six classic start tracks should be set (even though the race was in skating technique), the Chief of Course suggested setting the tracks on Thursday night.  With snow in the weather forecast for the next morning, this was perhaps an unwise idea, but by laying a cloth-cover over the approximately 30-metre-long start tracks and the timing equipment on the start line, the tracks were excellent the next morning when the cloth was rolled up in 15 minutes.  The rest of the sprint course was prepared (packed and tilled) for skating late the night before, and three snowmobiles with rollers/compactors were placed ready for use should more than an inch of snow fall in the morning before the competition started.

In principle, there are three preparation methods that can be used:

  1. Preparation with large grooming machine and tiller (approx. 6 meters wide and heavy PB 400/600)
  2. Preparation with smaller grooming machine and tiller (approx. 2.5 meters wide and lighter PB 100)
  3. Preparation with snowmobiles without tiller and with roller/struck

(Using larger and heavier grooming machines means that the snow needs longer to settle/freeze, so an organizer usually cannot prepare with a large machine just before the race starts, especially if the weather is mild) In addition to mechanical equipment, the Chief of Course also has a forerunner team at his disposal on race day (the Chief of Course for the World Cup and World Cup 2025 is long-time volunteer Chief of Course in Granåsen, Tore Hammer).  Prior to both the sprint prologue and the finals, with less than an inch of snow, the forerunners (instead of machines) were used to “break down” the new snow around the course.  Since it snowed steadily, the forerunners skied several laps of the sprint course, and at the end of the day, the GPS clock showed that they had covered between 30 and 40 km.  A good training day for the group from Heimdal High School!

DAY 2 – Saturday (Skiathlon):

The weather forecast for the next day (Saturday) showed a lot of rain overnight and during the day, so the preparation with two groomers was postponed until 2 a.m., and the course for the race were then first tilled and smoothed out.  The classic tracks were then set from 3 a.m.  The starting tracks in the stadium were set with the PB100 machine and by using the GPS equipment in the machine (instead of the driver manually setting the tracks by following poles or the like).  The GPS values had been measured and loaded using the municipality’s GPS meter and phone app.

Around one of the skiathlon courses, four classic tracks were set in the best possible ideal line.  Optimally (and for the World Championships next year) the municipality will use a 4-track pan and large groomer, but since this track pan was not in place, two laps of the PB 100 machine were run and two tracks were set at a time.  This will of course be a bit challenging for the driver (there should be 1 m 20 cm between all the tracks) on lap number two, but in the end, it turned out excellent.  Due to some challenges with the soft snow, the track setting was not finished until 7:00 am and this was just enough time for the moist snow to settle before the waxers showed up to test the skis.

DAY 3 – Sunday (Interval start classic):

The weather forecast for Sunday offered plus degrees overnight and a weather change to freezing temperatures between 9 a.m. and 10 a.m.  The Chief of Course suggested grooming as late as possible so that there was the least chance of the snow becoming icy when the temperature went below freezing.  Preparation started at 04:00 and was not finished until 07:00.  Due to the weather and temperature, the tiller/machine had to be run slowly to get good results.  Two machines were used “side by side” to till and smooth out the entire width of the course, and it was observed that it quickly became an edge in the middle.  Perhaps a third machine should have been used as well?  As usual, a PB100 machine was used to put a classic ideal-line track around most of the course.  In addition, two tracks were set out from the stadium/lap-lane and the first 300 meters.  Two tracks were also set in the last 500 metres (a gentle and straight ascent towards and up the last hill).

In summary, it was a great World Cup and World Championship test with many challenges for those responsible for the preparation of the courses.  The result was impressive and the group is now rich in good experiences for next year’s Championship.  The 2025 World Championship extends over almost 3 weeks, and in Trøndelag this usually means a dose of all kinds of weather types.

New FIS guideline for salting of ski jump hills

The FIS ski jumping committee has released a new guideline for how to best salt or fertilize snow in soft and wet snow conditions. The document is based on FIS’ own salting guideline for Cross-Country courses, and includes more details, photos and information specific to ski jumps.

The document can be downloaded here or found on the home page top menu under “Literature”.

Finland on the forefront of snow storage

While the glaciers are melting around the World, Finland is building new ones.  A Scandinavian delegation recently visited Levi and learned how Finland over many years has built competency and snow depots to secure early season openings and snow guarantee for their World Cup events.  What they have achieved in Levi in the middle of flat Lapland is no less than exceptional!  Here they go for it with a Finish sisu!  The snow storage is over 200 000 cubic meter large and distributed along the courses, ready to welcome skiing tourists and National Teams from all over Europe.  The insulation material Finnfoam may become the new buzzword for everyone thinking about snow storage in the future.  This is without doubt a solution for the future where cooperation across borders will benefit our ski sport.