This report might help:http://www.skierslodge.com/webcam.html
Les Deux Alpes, over the top of La Grave is reporting half its pistes closed, and the general picture across the French Alps is near-zero off-piste.
So, all in all, I'd hold your horses for a good while yet.
From my experience of skiing La Grave, I'd think it would need at least 1 metre of consolidated snow cover on top of the paltry 20/30cm that's there at the moment.
Lots of rocks to be covered!