Possible in theory, but you need to file your board edges fully round so they can't cut in the wood. And I mean so round that you can drag your face on them and they won't cut (don't try that though). Wet wood is quite soft so it's hard but i have seen people do boardslides on wooden handrails. Snow probably doesn't help, but maybe if you can melt it a little and let it freeze into ice, that could help. Not sure, just guessing here. And the oldest trick in the book is to rub candle or some kinda wax on it. Can't really recommend it though since I don't know what people think if you go wax their handrail... but in theory that could help
You know when an edit/movie has that B-Roll with the guys spraying water out of their mouths on to the lips? Yeah you want to do that to the wood so that there is a thin layer of ice so it slides better.
I've ridden rails in the river valley here made of wood, just short ones but they grab like nobodies business. Probably why you mostly just see guys doing 50-50's and presses on them, turn sideways and your asking for it. A little layer of ice won't do much of anything at all.