RE: Winter Storage - frozen
Up here in Finland we have decent winters, still snowy and cold. Lots of people store their equipment in cold spaces over the winter, and I don't think I have heared about any casulty. I have myself stored the board cold for maybe 10 seasons...
But it sure feels better if you take them in and let them dry first. With bag, without bag, went screw open/closed: it does not seem to matter.