We did this hike from Green Lakes camping area as a warm up for South Sister the following day. Nothing great until you gain the ridge but after that, the climbing is more exciting and there is a slight feeling of exposure. The final section is a bit airy with a few easy moves and a skirt across an exposed ledge to the summit. Views from the top into the guts of the old volcano are great.
Broken Top, as the name implies, is an old shattered, crumbly mountain. Looking at it from the south, you will notice that the entire southern side has fallen, leaving a 2000 ft -near vertical- scree slope. It is this exposure you will be facing as you make your way up the final ledges to the summit. On the day we were there, we were essentially looking down into the cloud.
We got an early start at 0600. After a few miles we reached the beautiful Green Lakes area where we could see the saddle that we would be shooting for to gain the Northwest ridge. After about 1/2 hour of moving through dense woods we passed into a much clearer area where the saddle was only a little further away. From here it got pretty steep climbing across scree and loose dirt. After we gained the ridge we marked our entry point to help with the decent because a weather system had started to move in. We continued up the ridge until we came to the only Glacier on the mountain(very very small). We skirted past it and came to the bulge on the ridge just short of the summit. I lead the small pitch and set up a fixed line that our group prussiked up. Meanwhile visibility had about went down to zero. Within a few short minutes and a precarious walk across an exposed knife ridge we were on the summit.