OTIRA - ROLLESTON RIVER - WAIMAKARIRI COL
From the rail bridge on the Rolleston River, follow the true left of the river for about 500 metres until above the obvious bluff on the opposite bank. Cross to the true right and continue upstream utilising several sections of marked track.
As the gorge is approached the route rises steeply up an often dry side creek. Climb some 70 vertical metres before entering a marked trail on the true left. It sidles the hillside for an hour or more, crossing scree gullies and bush, then descends a scree gully back to the river-bed. A boulder hop of some 200m finds several cairns marking a steep pitch on the true left. Negotiate the so-called track (scree slope marked with cairns) upwards until the track levels out on the scree & avalanche slopes below Anderson Peak and Mount Armstrong. Theoretically a track sidles this face, but is generally too vague to recognise let alone follow. The best option is to sidle the contour on the true left, crossing scree gullies and avalanche chutes (these chutes can be still active into early summer - especially below Mt Armstrong - beware!).
Eventually your route should skim under some bluffs to the east, finding a series of grassy ridges that should be slowly ascended. This tops out in a basin (head-waters) below Waimakariri Col. Follow a stream fed by the glacier running onto the col from Mount Armstrong. When at the same level as the col, cut across a scree and boulder field to the tarn on the col. Time from the railway bridge to the col is upwards of 6 hours.
OTHER TRAMPING ROUTES
A track system exists on the eastern side of the National Park. These include the catchments of the Poulter and Esk Rivers, and Andrews Stream. These routes tend to be quite straight forward and easy going, as the climb in altitude in this area of the park tends to be gradual. Information on these routes is available by consulting the "Route Guide Series" of Arthur's Pass National Park.