I recommend having a mountaineering setup for those really wet days. No snowboarding specific gear holds up to terrible conditions like mountaineering gear. I have Mountain Hardwear Exposure II bibs and a North Face expedition shell for those really nasty days.
A lot of the water saturation (wet out) will be detrimental to the type of fabric that is used. Nylon fabric, with a 15000mm/15000gm/24 rating, will saturate quicker that a twill or herribone fabric that is 8000mm/8000gm/24hr rating.
For re-waterproofing, make sure you use a DWR spray (Grangers, Nikwax, Stormproof)& read the instructions on the clothing.
Depending on how heavy the snow or rain is, will be a factor to how fast the material wets out.