A news release says the mountain's ski patrol, a paramedic and doctor responded to a tree well incident at about 11:15 a.m.
People tried reviving the man with CPR while he was being transported down the mountain, but he was pronounced dead at the Whistler Health Care Centre.
The man's identity has not been released.
Tree wells are holes or depressions that form around the base of a tree while snow builds up.
Tree well incidents occur when a person falls head first into an area of deep snow around the base of a tree and become immobilized.