a neat trick you will find when rapping off a bollard with the rope directly around the bollasrd is related to pressure melting. you see when you are on rap the rope exerts pressure on the hard snow causing surficial melting. when you go off rap, wham, no pressure, melt freezes almost instantly and the ice instanly freezes your rope to the snow making for a cluster fuck trying to pull it down.
so: pll on BOTH ends hard (causing the melt again) then suddenly let go of one and you should be able to pull it without it freezing again.
i read about this somewhere, then tried it myself and it worked.
but in general "Bollards are the cheapest anchor available. Each one only costs about a year of your life expectancy." - Bill Durtler.