GENEVA (AP) — World champion extreme snowboarder Estelle Balet was killed in an avalanche on Tuesday while making a film in her native Switzerland.

Police said the 21-year-old Swiss athlete was struck by the snow slide early in the morning above Orsieres, near Switzerland's southern border with France and Italy.

She had been following another snowboarder, who was not caught in the avalanche.

Valais state police said in a statement that rescuers were able to free Balet, who had been wearing special safety equipment, but she died at the scene. An investigation into the cause has been launched.

Two days earlier, Balet had looked forward to her filming work in a message posted on her Instagram account.

"Pretty awesome to get to snowboard with this view.. Can't wait for more filming next week !" she had written.

Balet recently won the Freeride World Tour for a second straight year racing as a member of watchmaker Swatch's professional team.

The global series challenges snowboarders and skiers in extreme conditions on ungroomed snow, and is organized outside the Olympic system.

"Estelle Balet was a naturally gifted shining star and demonstrated remarkable talent," the Freeride series said in a statement on its website.

"The Freeride community has experienced a tremendous loss today," the statement said. "Our thoughts are with the family and friends of Estelle Balet as we send our deepest sympathy and condolences during this very difficult time."