Donza is on the money here. The feedback we heard in Thredbo last Friday was that unusual atmospheric conditions had brought the moisture in the saturated snowpack to the surface during the night. The wind combined with the cooling temps to set the moisture into a rock hard glazed ice. I skied from when the mountain opened around 11ish, and I can tell you the sun glare reflecting off the glaze was bizarre...it was like a mirror in parts. On a couple of occasions I skied to the edge of the regroomed runs and drove the tip of my pole into the ice....I could barely chip it. As already stated, the off piste was unskiable and in my opinion was extremely dangerous for all riders regardless of ability. I applaud Thredbo for their decision to open late in this instance. Undoubtedly they made the right decision on behalf of their guests and their staff.