I was going to mention Mt Baldy (SoCal) as well. Here's how the Tour folks break things down:

* CAT. 4 Usually less than 3km in length, an easy pitch that amounts to no more than a sustained rise in the road.
* CAT. 3 Slightly harder, up to 5km in length.
* CAT. 2 Between 5km and 10km, and steeper than a 4-percent grade.
* CAT. 1 Long and steep. Between 10km and 20km, and steeper than a 5-percent grade.
* HORS CATÉGORIE (HC) or Above Category -The longest, steepest mountain climbs. Extremely difficult, sometimes 15km to 20km, with grades often exceeding 10 percent.


The backside of Big Bear Hwy 18 coming up from the desert has got to be Cat 1 or HC. I'd come up it in a school bus in high school, and man, what a ride, from the desert floor up to the snow....