The Indian summer is over. Temperatures have plummeted from 20C to 11C in the Swiss Valleys according to MeteoSuisse and there will be fresh snowfall above 1300 meters with some 30-50cm expected over 2000 meters on the north side of the Alpes to the Berner Oberland. Winds have also been getting up with gusts of over 130 km/h in the mountains. The SLF have given the avalanche danger as Considerable (3/5) for the Jungfrau to the Alpes Glaronaises and the Prättigau for Monday and Tuesday. The danger is principally localized on south facing slopes covered with wind blown snow above 2800 meters. The danger is particuarly on smooth terrain. There is also a risk in couloirs etc where the principal danger will be of being carried by a small slide. The danger will decrease slowly.
There was also a dusting of snow in the French mountains above 3000 meters on Saturday night as this photo of the Grandes Rousses shows. Given the wind I would imagine that routes such as the Tacul on Mont Blanc could be dangerous. Speak to the Chamonix guides office or OHM.