A small number of people are believed to be injured and more are stranded on chairlifts after the incident, which happened around 3.25pm.
There are no details on the extent of injuries as yet, but the focus is currently on evacuating those injured and rescuing those who remain on the chairlift.
More top news
Two people have been injured in a house explosion this morning.
Lactalis and health authorities have ordered an international recall after it emerged products may be contaminated with salmonella.
Chelsea Lauren posted a video to Instagram that appears to show Josh Homme striking a woman holding a camera with his foot.