Well, I think only the Aerial Tramway - or a representative can speak for what their protocols/procedures are for a situation like this.

However, as we all know, mountaineering/hiking is a sport that carries certain inherent dangers, which is why it is important to always be prepared. While I am in no way defending the decision to leave people on the mountain, the Tramway is a private company with its own set of legal and ethical responsibilities, especially to its employees. With respect to the specific conditions, I think most if not all people who viewed the forecast on Friday/Saturday, or before could tell that the weather would be challenging, to put it mildly, so there was advance warning to be prepared for the conditions at hand. Happily, however, its good to know that everyone survived.