The North Ridge is an exposed, spectacular ridgeline which is generally lacking the severe cornice problems of other ridges in the range, and can be accessed by a short, steep technical ramp. Close views of the giants of the Cordillera Blanca are constant throughout, and add grandeur to this otherwise shorter summit.
From Huaraz head to Quebrada Llaca and find a well-tread trail ~1/2km from the end of the road heading uphill. Be prepared to pay a road toll ~5km from the trailhead and check in with the National Park rangers at the end of the road before embarking on the climb.
Follow the trail uphill over dirty slabs, mud, and steep dirt to where the trail bends sharply West, climber's left. From here depart over steep grass and scree East 2km towards a prominent notch in the South-trending ridge coming from the summit, 200m or so higher than the last sharp turn in the trail.
A steep, loose gully 100m tall leads from the scree to a notch giving access to the Southeast side of Vallunaraju. Another 2km over talus leads to the last level ground with running water nearby.
From the level ground among talus and running water head uphill to the left-most snow and ice-covered ramp tranding climber's right, East, to the North Ridge crest. The ramp has 200 meters of 50-80 degree snow, ice, and mixed terrain culminating on the North Ridge.
Follow the ridge crest South and then West to the summit over lightly-crevassed and lightly-corniced terrain.
Conditions on this route, the ramp in particular, vary dramatically, ranging from loose snow over rock to solid ice.
Descend the North ridge and carefully downclimb or rappel the ramp using v-threads or rock anchors.
Or descend the standard route following the well-marked trail back to the trailhead. Any camps for this option would have to either be carried over or located near the turn-off from the standard route trail.
In order to be prepared for a variety of conditions crampons, ice axe/tools, ice screws, pickets, rock gear to 1" with pins, and a rope at least 50 meters long should be taken.