Let it snow! Environmental risks factors of artificial snow in winter sports

Overview

In a winter sports industry that saw rapid expansion over the past decades, artificial snow now [1] plays a central role that typically covers 15 – 25% of a resort’s operating budget, although costs can be as high as 50% [1]. The production of artificial snow is an extremely costly process for winter sports resorts. In the Alps for example, almost all resorts rely on artificial snow [2]. This reliance is more critical than merely extending the season or improving the tourists’ skiing experience. Because of climatic changes, many resorts can no longer rely on natural snow at all and snowmaking equipment is now ubiquitous in the Alps.
There are two types of snowmaker in common use: snow lances and fan guns. Both machines use a set of nozzles of various sizes to produce fine mist from a mixture of water and air. Because the freezing process depends on environmental parameters, a pre-programmed algorithm controls nozzle settings, the air/water mixture and the throughput.
Both types of snowmaker rely on temperatures low enough for the water mist to freeze. Additives can be mixed with the water to increase the operating temperature. These additives, mostly ice-nucleating proteins (INPs), facilitate nucleation, thus increasing the maximum temperatures artificial snow can be produced in.
The use of INPs is controversial. Although their use is widespread e.g. in the US, they are currently banned in Europe. However, the current rate of climate change suggests that the ability to produce artificial snow at higher temperatures is vital for the survival of the European winter sports industry.
In a winter sports industry that saw rapid expansion over the past decades, artificial snow now [1] plays a central role that typically covers 15 – 25% of a resort’s operating budget, although costs can be as high as 50% [1]. The production of artificial snow is an extremely costly process for winter sports resorts. In the Alps for example, almost all resorts rely on artificial snow [2]. This reliance is more critical than merely extending the season or improving the tourists’ skiing experience. Because of climatic changes, many resorts can no longer rely on natural snow at all and snowmaking equipment is now ubiquitous in the Alps.
There are two types of snowmaker in common use: snow lances and fan guns. Both machines use a set of nozzles of various sizes to produce fine mist from a mixture of water and air. Because the freezing process depends on environmental parameters, a pre-programmed algorithm controls nozzle settings, the air/water mixture and the throughput.
Both types of snowmaker rely on temperatures low enough for the water mist to freeze. Additives can be mixed with the water to increase the operating temperature. These additives, mostly ice-nucleating proteins (INPs), facilitate nucleation, thus increasing the maximum temperatures artificial snow can be produced in.
The use of INPs is controversial. Although their use is widespread e.g. in the US, they are currently banned in Europe. However, the current rate of climate change suggests that the ability to produce artificial snow at higher temperatures is vital for the survival of the European winter sports industry.
The aim of this project is to investigate the effect common additives have on the behaviour of artificial snow. This topic is not only important with regard to soil and water contamination but also with regard to the total water and energy balance of snow production. The key science questions of this project are:
1. Do snow properties differ mechanically or thermophysically, depending on the type of additive?
2. Do snow microstructure or sintering behaviour change?
3. What are the risks associated with using additives and what are timescales for additives to break down?
Answering these questions is key to assessing the overall impact of artificial snow, both in terms of resource utilisation and environmental protection.

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Image Captions

Snow cannon in the alps

Methodology

This interdisciplinary project will integrate the thermodynamic and biochemical aspects of artificial snow usage, combining laboratory and field investigations with mathematical models.
Questions 1 and 2 will be addressed by creating samples of artificial snow in the Stirling Planetary Ices Laboratory. The samples’ sintering behaviour will be observed and optical as well as mechanical measurements will be made to characterise the sample. In order to provide real-life reference measurements in a variety of climate conditions, the same optical and mechanical experiments carried out in the laboratory will be replicated in the field on both natural and artificial snow; artificial snow is in use both in the Cairngorms and in Glencoe in Scotland. We expect both artificial and natural snow to be available in the field.
Questions 2 and 3 revolve around microbial interactions. Microbes on glacier surfaces may not only be important for breaking down anthropogenic contaminants (including INPs), but also have a secondary impact on the snow’s optical properties with potential feedbacks on glacier melting [4].

Project Timeline

Year 1

The experimental work of this project will take approximately 30 months to complete.
Year 1 will be used for familiarisation with artificial snow production, both in the laboratory and in the field. Methods for assessing snow characteristics will be devised, experimental procedures will be developed and a suitable model identified. Attendance at a winter sports trade show might offer an opportunity to gain insights into how the industry responds to the environmental challenges.

Year 2

In year 2, the ability of glacier and downstream proglacial stream microorganisms to break down additives in artificial snow (including INPs) will be assessed via a series of microcosm experiments replicating in situ conditions (temperature, light irradiation, nutrient content, microbial inocula) with INP breakdown monitored over time by ‘drop freeze’ assays ground-truthed to liquid chromatography-mass spectrometry (LC-MS). Further field sampling and linked laboratory experiments will test if the in situ colonization of artificial snow by microorganisms can alter its physical and optical properties.
Year 2 activities will include collecting field data and comparing them to laboratory measurements. At the end of year 2, we expect to be able to have a full understanding of the physical behaviour of artificial snow with various contaminants and an advanced understanding of the role of microbial activity.

Year 3

The lessons learned w.r.t. equipment and procedures suitable in the field will be applied at the beginning of year 3. Documenting and disseminating the results will begin shortly afterwards.

Year 3.5

The final months of this project will be dedicated solely to writing up.

Training
& Skills

The studentship will provide an opportunity to build an interdisciplinary research career in environmental and climate studies, with insights into energy studies and aspects of sustainable tourism.
Skills development during fieldwork will include training in sampling techniques; experiment design and analytical techniques will be acquired during laboratory work, while data handling, manipulation and integration skills can be honed using modelling software.

References & further reading

[1] Brown, R. (1997). Man-made snow. Scientific American 1, 100.[2] Asden, L. (2018). Is skiing in Scotland on its last legs? The Telegraph, 21 Feb 2018.[3] Snowmakers are saving ski resorts – for now. MNN.com. 3 Feb, 2014.[4] Lutz, S. et al. (2016). The biogeography of red snow microbiomes and their role in melting arctic glaciers. Nature Communications 7 https://www.nature.com/articles/ncomms11968

Further Information

For informal enquiries, contact Dr Axel Hagermannn (axel.hagermann@stir.ac.uk) tel: 01786 466557

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