Frozen assets Ski resorts keep their snowfall on ice to beat the climate crisis

Before the arrival of electric fridges and freezers, people across Finland would saw a block of ice from a river or lake before the spring thaw, thickly cover it in an insulating layer of sawdust, and stack it in a barn, pit or ice cellar to be protected from the warm air of the summer months.

- Miranda Bryant

In a time of global heating and increasingly unpredictable shorter winters, a contemporary twist on the traditional jään säilöminen (ice preservation) technique is now being touted as a potential solution to save Europe's struggling low and medium altitude ski resorts.

The large French Alpine ski resort Alpe du Grand Serre in the Isère last month announced that it had been forced to close because it could not afford to become a year-round destination to offset its shorter winter season.

Sawdust has been used above ground for decades to preserve snow in Finland for winter sports and, more recently, a version using mats made of extruded polystyrene, the same material also used in home insulation across the Nordics, with a claimed use life of more than 20 years.

The mats have been in use at ski resorts in Finland for several years - including at Levi in Kittilä and Ruka in Kuusamo - but this is the first season its developers, Snow Secure, have supplied snow storage outside of Finland.