The far side of the crater then descends steeply, and the slope is covered in thick ash, along with small fragments of volcanic rock. The easiest way to walk down is to dig your heels in deep at each step; it took me half the slope to get a grip on this technique.
This photo, from the bottom looking up, doesn't really show how steep it is. If you slip (which I did), you just slide a way on your bottom. So long as you stay on the ridge, it's not too bad actually; the ash is lovely and warm after the cold climb. But it creates a small rockslide for the people below which isn't so good.
And there are lots of people! There must have been over 1000 people on the crossing that day, and that's far from unusual. Tourists are bussed in and chucked out into this harsh terrain, and collected the other end. One lass I talked to (a young Swede) didn't even realise she was walking on an active volcano. I was probably one of the slowest walkers that day (a combination of unfitness and a perennial desire to look around, stroke bits of lichen, contemplate the rocks, take pictures and so on.) But I was properly equipped; I saw people in that icy cloud in glittery plimsolls and beach shorts. Not happy people, I have to say.
This track costs a fortune to maintain. Theoretically the bus companies give part of their fee (typically $30) to DOC for this cost, but nothing requires them to do so, or charges the individual tramper. We both think that NZ needs to think of a way of charging tourists, particularly rich world visitors, for their use and abuse of the country's environment.