One user, @jaskiretxo, said: "Poonam Bhattal a beautiful girl who we were all so lucky to have known, may our thoughts be with Amreeta and her family. RIP beautiful xox".
Another, @TharanVirdi, posted a photo of a girl wearing black-rimmed glasses, and said: "Poonam, You will be dearly missed, thoughts and prayers go out to your family. Waheguru #gonetoosoon #RipPoonam x".
Local police commissioner Francesco Destro told Sky News: "The ski lift was moving very fast and rising fast when she fell." He said he could not recall a similar accident.
Mr Destro added that the girl initially answered questions when officers rushed to her aid but "did not make it".
Police have launched an investigation and are due to question the teenager's classmates, who boarded the lift with her.