After having produced or stored the snow, distributed and then groomed it properly for skiing or competitions, it is important to know how to best prolong and preserve the snow, especially in mild or wet weather conditions, or when old snow becomes very soft.  With proper knowledge and application, salting and watering can freeze, harden and preserve the snow. Salting is done in all snow disciplines, and mostly for competitions. Watering and water injections are mainly performed on alpine slopes and ski jumping hills.  Harvesting natural snow may also be a applicable technique for certain alpine resorts.