Workers required heavy machinery to clear snow walls up to seven metres high as extreme weather caused chaos across parts of France and Switzerland.
- Avalanche of "extraordinary breadth" after days of extreme snowfall in the Alps
- Work to cut through avalanche results in snow walls up to 7m high along a 250m stretch
- Train services resume to help evacuate 13,000 stranded tourists in Swiss ski resort of Zermatt
Up to 1.8m of snow fell inside 36 hours in parts of France's Savoie region, creating avalanches, cutting off towns and causing loss of power.
A large avalanche that crushed trees and rocks cut the valley road between Bessans and Bonneval-sur-Arc in the Savoie region, close to the French and Italian border, and work to clear the drift caused snow walls between four and seven metres along a 250m stretch.
Snow and avalanche expert Alain Duclos, president of the Data-Avalanche association, told French media avalanches of this size were rare, while he had never seen the walls that long or thick in his 30-year career.
He said the drift had an "extraordinary breadth".
Work continues to evacuate stranded tourists
Meanwhile, train services resumed to continue the evacuation of 13,000 visitors from the Swiss resort town of Zermatt, near the famed Matterhorn mountain.
Extreme snow and an avalanche risk saw thousands of visitors stranded for two days earlier this week, with helicopter proving the only way out.
"After being cut off for almost two days, Zermatt can now be accessed by train again," the local tourism office said.
Teams were working "as a matter of urgency" to try to open roads to the Swiss Alpine town.
The move came as Switzerland's avalanche institute, SLF, lowered the avalanche risk from the highest level, five, to four.
Local officials had initially hoped to get trains moving earlier, but the timetable was delayed after helicopter crews spotted a new snow mass left over from an avalanche days earlier.
Zermatt's Mayor Romy Biner-Hauser said "heavier machinery was needed … and that's why the operation is live only now again".
She said she expected roads to be passable sometime on Thursday (local time).
Swiss officials said no lives were ever in danger and the situation was calm, with cafes open and many streets walkable.
"The guests and local residents weren't placed in any danger at any time — they had power and supplies," the Zermatt tourism office said.
Some visitors were more upset that nearby ski slopes were closed than getting stranded in the posh, picturesque resort town.
"Unfortunately, no skiing today," said Kurt Tulleners, a visitor from Hong Kong, before the train service resumed.
"So yeah, we're just kind of stuck."