The high, open pistes lack the contrast required for orientation during white out conditions and slope and sky can blur into one.
However, there are certain runs that offer more contrast providing vast amounts of skiing/snowboarding when the flakes are falling. The trick is to head for the pistes that are tree-lined, as they help provide definition when everything else seems to be white.
Bear in mind that the valley itself can be covered in an all-encompassing fog, but the top of the mountains can be bathed in glorious sunshine (check out the webcams!). Also, if it’s lashing down with rain in the valley, it means it’s snowing up top, giving you the best and freshest powder you’re likely to ski on! And because it’s a bad weather day, chances are, you’ll have the mountain to yourself.