At the head of the Rolleston River make your way up through the rock buttress on the true-left of the river to gain access to the Southeast Spur, from here follow a line of good rock that takes you up to the 2010m point of the east ridge. The East Ridge can be followed all the way to the summit of Mt Armstrong. Starting as a broad ridge at 2010m, the east ridge progressively narrows until it involves climbing around some loose pinnacles of rock with a decent amount of exposure on both sides, before broadening out again just before the summit.
- Alpine (Technical) 2+
- Alpine (Commitment) II