The Therma Glacier route is to the left of the NW Ridge as you ascend...good way up in early season as need a lot of snow and ice on top of the steep rock slabs to ascend to the flat spot at 2500m height (where the Ramp also joins up from the other side). Can be a very risky route later in the season due to threat from serac and ice cliffs collapsing above you or even below you whilst you are climbing up them...!!! We climbed it in Jan 2006 with awesome crevasses and knife blade ice ridges to walk along followed by an easy pitch of rock climbing. Two days later we saw the whole of the Therma route smashed into a million tonnes of snow and ice at the base of the ridge!!! Timing is everything in the mountains...