isn't there a produce called No Sno or something like that, that is made just for that reason. I've seen it at my local pro shop.
Yes, it is a silicon based product. I've used it in the past, but like most products it won't work in a saturating rain. And it works best if it is fresh. Lately, I use hair spray on the feathers if I think it is going to rain the next day. It also has limited life though. I've tried the powder, but itis too messy for me and trying to get even distribution is tough.