I like the convenience of having a backpack when I ski. 

Last winter one of the lifties at the local ski hill gave me guff about my backpack, claiming that it was unsafe. I wore the same backpack to different slopes around the Northeast US all winter, and he was the only person to ever say anything about my backpack being unsafe. 

Is it unsafe to ski or ride the [chair lift](https://en.wikipedia.org/wiki/Chairlift) with a backpack? If so, what are the associated risks?
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