Your eyes are instrumental in aligning your balance to the levels present in your inner ear- if the sight alignment picture is off by even the faintest of seconds - headaches, dizziness, and nausea can result.
I have been caught in whiteouts while backcountry skiing and snowboarding that were so severe that you could topple over while just standing still, because of the loss of reference on the horizon.
It's all too common here in the dense and foggy conditions of the Wet Coast- I figure that some of the erratic lines shown in yesterday's Olympic PGS mens final might have been from vertigo's side effects.
A carver's haiku-
My board's a scalpel,
To carve deep ruts in the snow,
Is my destiny.