Tour climbs are classified in five somewhat arbitrary categories:

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.


It kinda sounds hard to me