Keep in mind that weather and snowfall vary greatly from Portillo and Las Lenas to Patagonia due to their distances.
Generally large Pacific storms make landfall in Patagonia and the Lake District of Chile dumping snow for days on Pucon, Cerro Bayo, Bariloche and San Martin de Los Andes, and then on to Lonquimay and Termas de Chillan (Nevados de Chillan) and working their way North towards Valle Nevado and Portillo over a period of days. Generally if it is raining in Santiago, Chile, it is snowing in Valle Nevado and Portillo and often Las Lenas.