That's certainly on the route, but less relevant than the hail, as they could have diverted over the dam, without going down into Brevieres. I've cycled that way myself, a long time ago.
It explains how the Tour entourage still made it into Tignes.
There's be a lot of moaning about this in Tignes and Val. They already feel that the lift-pass prices have been pushed up by promotions such as this. Very unfortunate for them.