http://www.infokop.net/index.php?option=com_content&task=view&id=2434
(Blue is natural snow height, red is temperature). This is for 2016/2017 season. There is dropdown menu you can select other years.
You have lot of info about Kopaonik on this site including live cameras and it's in english (statistics in this link are only in Serbian) and this is link to english version www.infokop.com