Bookworm,
Please don't jump so strongly to the defence; I noted that your profile doesn't even say if you fly or not and I think it is important to know from which corner folk are arguing from.
I have already done my own research, some years ago and every winter. I've been required to operate in European winters since 1977. The aircraft I've flown most have had no icing clearance or de-icing equipment fitted. They have also, with one exception, been unpressurised and therefore unable to climb above snow or icing cloud. My job has been therefore "in it" or close to it.
A presentation I was asked to give on aircraft icing problems in the mid 1980s was purloined and used by the RAF for some years afterwards, most particularly by 33 (AMF) helicopter squadron, who operated in Norway in the winter. The brief's probably been replaced since Powerpoint etc came along but it might still be lurking in a box somewhere at RAF Odiham.
Although I no longer consider myself FW current I do have FW experience, light SEP and single jet, btw (hence my profile saying "QFI" as well as "QHI". I also hold a CPLA.
Before I bow out of this discussion, I repeat my sole purpose on this thread, which is to put out my own advice that generalisations, with regard to aircraft operating in falling snow and cold cloud conditions are best avoided.
Each manufacturer who wishes to obtain an icing clearance for a particular aircraft is required to test fly the aircraft and prove that it is safe to do so. There is NO "one size fits all" solution to safe operations in winter conditions.