If you shoot a GL2:
The light meter on the GL2 in flat light is total shit. you must, according to the light meter, over expose by 1 or 2 notches.* it might look like shit through the viewfinder and lcd but trust me, it will come out perfect if you do it right.
*determine over-exposure amount based on how much snow dominates the screen. ex. if there are trees in the shot, only do 1 notch. if its above the tree line and there arent much blacks or colors, do 2 notches. only in very extreme cases of flat light should you do 3 notches, but I do not recommend it, for it rarely works.