Search continues after four fatalities were reported in an avalanche near the French Alps resort of Tignes on Feb 13, 2017. [Photo/VCG]

All four fatalities - a 49-year-old instructor, a 48-year-old father, his 15-year-old son and a 19-year-old half-brother - are believed to be French but were not identified by officials by name.

They had been walking off piste - snowboards in hand - with a guide near the main Tignes slopes when the avalanche hit, Martrenchard said, adding that they were equipped with locator devices.