Indoor skiing is relatively new activity. It was developed because regular winter skiing is so popular in Finland that many people want to do it all year.
Indoor skiing requires so called ski tunnel, where either artificail or natural snow is preserved. The air and snow temperature is maintained at several degrees below zero (32F) so that skiing is possible regardless of the weather outside.
There are currently 6 ski tunnels in Finland and 3 more are being developed.
In Helsinki, the Ylläshalli ski tunnel is visited by tens of thousand people each year. One of the reasons for indoor skiing popularity is its affordable pricing. Single ticket only costs 14 EUR ($17).
In Leppävirta, the Vesileppis ski tunnel is located underground. It is situated under the hotel, so that hotel guests can ski free of charge. The hotel also features an aquapark.