system
Given the following post, respond as if you're commenting on Reddit:
human
Why doesn't ice and snow pile up much higher at the poles?

It seems to me that the accumulation should be almost continuous until the pile gets so high it starts flowing back via gravity/erosion.  There is constant precipitation (I assume) and there seems to be very little opportunity for the accumulated ice and snow to return to the atmosphere.  Can natural evaporation really balance the continued precipitation at those low temperatures?
gpt
The problem is where you assume constant precipitation.  

That's wrong.   The poles are very dry and get very little precipitation.   The air is so cold that all the moisture has already frozen out of it before it makes it to the poles, and there is little humidity left.