Looking down Snake Dike Yosemite 1976

I've been posting the wrong stuff under 'history' I guess. Here is where I should park all my old 70's photos from the Needles I see!
this photo has me puzzled. it looks like a snow route below, but then has short runners up the 'headwall'? which looks low angle actually in this shot. Explain the climb for us 'noobs who have never been there.

Snake Dike basically traverses the rounded part of Half Dome in Yosemite (you get down using the cables). The dike you climb on is a rougher type of rock that is like a road in the granite. Without this, it would be too steep and holdless to climb in most places. Since the climbing is moderate, there is only one bolt to protect the pitch. This scan is from a picture taken with a very cheap camera.