Camped on Ptarmigan ridge for 2 nights Wednesday and Thursday. Sustained winds 10-20 mph continuous over that period created very deep wind slabs on slopes below camp. As storm rolled in this afternoon we observed almost 4 inches of grapple over the area followed by continuous heavy snowfall. Wind slabs did not seem to be too reactive but triggering one would be very bad due to the thickness which in one spot appeared to be almost a meter deep.