Anyway, I have been over that pass, and most others, in full on white out blizzards. One time, they closed the road after I started up as the weather conditions were so bad. When I came down the other side, the Sherrif and the CDOT folks were quite amazed that I made it. I have also been on roads that if it were not for the reflector markers on the little poles, I would not know where the road is. Kind of take it on faith that there is road beneath the rubber.
Reminds me of http://en.wikipedia.org/wiki/Ice_Road_Truckers. Not saying its the exact same thing, just reminnds me of it.