The Casma route begins in a large floodplain before beginning the endless switchbacks up a 2,800-meter pass over the Cordillera Negra [1], at which point a full view of the snow-covered Cordillera Blanca [2] swings into view. From here the road drops directly into Huaraz [3], nestled in the valley below.
The road is dirt, surprisingly smooth, and only takes six hours — though much longer in the rainy season. Leave for this journey early in the morning to enjoy spectacular views, as clouds tend to form in the afternoon.
The best time to take this route is April or May, at the end of the rainy season, when roads are somewhat dry and mountain fields are brimming with flowers.
Links:
[1] http://www.moon.com/destinations/peru/huaraz-and-the-cordillera-blanca/trekking-the-andes/cordillera-negra
[2] http://www.moon.com/destinations/peru/huaraz-and-the-cordillera-blanca/trekking-the-andes/cordillera-blanca
[3] http://www.moon.com/destinations/peru/huaraz-and-the-cordillera-blanca/huaraz