Snow storage is a way for ski resorts – especially in the country's middle and southern parts – to prepare for a milder climate with fewer snow days.
– It is a current issue this winter. In many parts of Sweden it has not even been cold enough to make snow, says Nina Lintzén, snow scientist at Luleå University of Technology and long-distance skier.
She is the lead author of a new study where different methods of snow storage have been investigated. With laboratory tests, researchers have compared how well commonly used cover materials such as bark, hay ensilage, sawdust and textile sheets protect the snow.
The melt rate in an insulated snow depot can be reduced by 70-85% depending on the thickness of the cover layer. Results from practical observations of different snow storages with various cover materials showed that the estimated melted volume of snow is usually between 15% and 30%.
– Today, mainly geotextile sheets and various wood-based materials are used for snow storage in Sweden. It is easy to get hold of and is quite cheap. Our research shows that sawdust is very good for snow storage. We have not actually found anything that is cheaper or better, says Nina Lintzén.
Air layer reduced melting
The results from the tests with sawdust of different ages clearly show that thermal insulating capacity is reduced with older material. The study also shows that bark insulates poorer than sawdust, and that hay ensilage is not recommended as cover material for snow storage. Adding an air layer between the textile sheet and the snow further reduced the melting.
Nina Lintzén has a number of recommendations for ski resorts that want to extend the season by storing snow:
- Cover the snow you want to save as early as possible, preferably before the melting has started.
- Find a sheltered and shady spot for the pile of snow. Make sure to have good draining of the melt water.
- Keep the surface area as small as possible without the pile becoming so steep that the cover material falls off. The snow pile's geometry plays a role in surface melting – the heat from the air affects more than the heat from the ground.
– With good planning, it is quite easy to store snow, but many people today do not know how to proceed. We would like to reach out with our findings, especially to smaller ski resorts, says Nina Lintzén, adding:
– It does not have to be that expensive to store snow – the costs are mainly transport and machinery.