Mt Thunder

Scramble from col at bottom (pickaxe head in grass - Bill O'Leary's?) ehich soon eases off to walking on blocks,over pt 1425, and then angle slightly right up scree slope above to gain the summit ridge via steep scrambling up a gully. Follow the ridge (straightfoward on broken but OK, granite) to the top. Accessed via sidle from Lk Truth outlet. Descent was along NW ridge to O'Leary Pass, involving one steep section of scrambling/downclimbing (as part of a longer traverse).