Paris - Tour de France planners are scrambling to find a solution to a landslide threatening the 20th and penultimate stage, the feared climb to L'Alpe d'Huez, where 250 000 tons of dirt and rock appear ready to fall.
Regional governor Jean-Pierre Barbier said : "The stage itself is not under threat, that's for sure, the Tour de France will get to l'Alpe-d'Huez.
"We're just not sure how yet."
The problem lies with the section of the climb above Lake Chambon where a 250 000 ton heap is moving forward at 10cm per day and which geologists predict will turn into a full blown landslide by early July.
A plan for a €5m alternative road has been approved and work is due to begin once central state authorities give it the green light.