So that's a Pennsylvania white out!
Ah yes, that's the stuff.
Most of the whiteout days I've been in have been three- or four-chair visibility, so nothing terribly bad.
As for whiteouts, I really don't know how the euros get used to them. I'm just amazed at the speed they'll ski in a whiteout on groomed runs. Absolutely insane some of them. It's not that you can't make turns, it's you have no idea what or who you'll run into. We were scared to just cross the trail, it's like crossing a street without being able to see cars coming.
Eventually, you just stop looking at the ground (because there's no point really) and focus on keeping good balance and skiing smoothly. You keep your eyes forward and check for blobs of color (usually another skier), piste markers, or the fluorescent padding around the snow guns. Those will alert you to the obstacles to avoid or course corrections to make.