Soutter won a bronze medal for Great Britain at the 2017 Youth Olympic Winter Festival and carried the British flag at the closing ceremony.

This month she was named in the senior GB squad for the snowboard cross Europa Cup circuit, and was tipped for a place at the 2022 Winter Olympics.

She had been training abroad in Europe, and died near her home in France.

No further details have been released about her death.

Writing on Facebook on Thursday, her father, Tony Soutter, said he was "so proud of the beautiful young woman she had turned into".

He added: "This cruel world took my soul mate and 'Bessie' from me yesterday on her 18th birthday. Ellie I will miss you more than you could have ever imagined. Rest in peace you little champion."

British Olympic Association chair Hugh Robertson and BOA Athlete Commission chair Ben Hawes said in a joint statement: "Ellie was an incredibly popular and well-liked member of the team.

"Our thoughts are with her family and friends at this sad time."

The statement said Soutter was due to return to competition next month after being selected for the GB team for the Junior World Championships in New Zealand.

"Ellie was one of the country's best up-and-coming snowboarders, competing in both snowboard cross and freeride," British Ski and Snowboard said in a statement.

Soutter during the Youth Olympic Winter Festival in 2017

Tributes - 'You were an amazing girl'

Eight-time British ski-cross champion Emily Sarsfield is among those to have paid tribute.

"So sad to hear the news of the passing of Ellie Souter. You really were an amazing girl," she posted on social media.

"Such a fun team-mate, made me smile every day, cracking all the jokes and enjoying life to its fullest. I'm going to miss you and your amazing energy. All my thoughts to your family."

British double Olympic skeleton champion Lizzy Yarnold on Twitter

Britain's 2010 Olympic skeleton champion Amy Williams said: "Such sad tragic news to wake up to. Thoughts and prayers go to Ellie Soutter's family."

Soutter's bronze was Team GB's only medal at the Youth Olympic Winter Festival in Turkey last year.

Team GB celebrated her medal with the Twitter message: "Tears of joy and snow stuffed down her back."

Speaking after her event, she said: "I cried as I crossed the line. I was just so emotional as it hasn't been the best season for me and it's finally on the way up.

"I even asked my coach to put snow down my back when I was in the start gate. It helps wake me up so I don't feel all floppy like a jellyfish.

"I just hope this isn't the last medal I win for Team GB. My goal is to compete at Beijing 2022."

Team GB said Soutter grew up in Oxted, Surrey, before moving to the Alps, where she trained.

Soutter (left) competing in snowboard cross at the European Youth Olympics Winter Festival in 2017