Meteo Chamonix www.meteo-chamonix.org is announcing a big drop in temperature for this week with temperatures between -4 and – 7 deg. even in the valley floors.
For more details (in French) check out this link:? http://www.meteo-chamonix.org/drupal/p-r-e-v-i-s-i-o-n-s/alpes-du-nord