That's what happened last season for the big race (whatever it was). Coupled with poor snow it meant the best part of half the mountain was out of action.
I imagine they will close off the tomba for a good 3 weeks prior. They water the piste to creat a hard snow pack. It would be scary as hell to ski down that.
It's a bit of a pain but at least the Chalin Valog area is open-as of last season. The runs there are excellent and very often quieter.
That race was a warm up for 2009. The race in 2009 is as i posted above (taken from teh FIS website).
I agree it is a shame. However, as I said before the runs at Chalin valog are equally as challenging. The black to the left of the chairlift as you come down is probably the most difficult in the resort IMO.