WD,
Seeing as you are from CA, I'd say it's a safe bet that you spend serious time in the SN's, no trees on top, and lot's of cold wind and snow that can happen in a moments notice. I'd always err on the safe side, and hump a few extra ounces for layering, than be shivering, or worse, and wishing you had them with you. But that's part of my personality anyway, I like taking risks, but calculated risks.

J.