In many ski resorts, some isolated and very windy like Aubrac (a kind of a reference in the matter), some sites are more exposed than others to wind and frost. The Chamonix valley has a few places like this, such as the cable car connecting the Plan de l'Aiguille to the Aiguille du Midi and the area of the Col de Balme located above the village of Le Tour. Regarding the Aiguille du Midi cable car, the manoeuvres of removing the ice from the cables are delicate and are made with the assistance of technicians and surveillance teams located upstream and downstream of the cable car station, which observe the behaviour of cables coated with frost. This work is very important because the ice may increase the diameter of the cable up to 70 cm, which is considerable. Then a technician placed on the gateway of the cable, will break the ice. This operation can take 1 h or 4 to 5 hours depending on the amount of ice. The weight of ice can exceed 40 tons, if we have in mind that the cable measures 40 mm in diameter and 30 tons. The Balme ski resort On this ski resort, the top of the chairlift's 'Tête de Balme' (2 200 m) frosts without any specific reason. We believe that this is due to the passage of a current of humid air retained by a bowl phenomenon, which causes a significant frost on the metal parts of the chairlift. This operation disturbs the chairlift, and this chairlift is essential for the proper functioning of the ski resort, providing access to the village of Vallorcine and vice versa. The defrost operation requires several hours of work, often during the night, and the operation often requires the assistance of technicians and the snow patrol. The operation is very technique and delicate. Example on Christmas day, it delayed the opening despite incessant work on the cables. Le Dauphiné
