They have been busy this week moving snow, so you can ride from the bottom of he glacier down. Thats would allow riding from 3200m, but I don't no how far they have got!
Even if it isn't open for riding, the lift is open for snowsports, so if you are doing he Mountain of Hell go and have a look from Jandri lift and get your bearings.
The Red Venosc run is usually used so get some practice in as it is pretty fun when rode fast. Also practice on all runs down from Diable, as they weave down that face too!
The talas from he lake down has been made better over the last couple of years. This is the one you can see as you drive in, weaving down under the chairlift.
Most of the riding is on the map and you will find that ok for a couple of days.