We’d been turned back on Rishiri-zan, so we had some unplanned time to work with on the way back to the hostel. So we made the quick detour up to Pon-yama. It was a relatively straight forward detour. A few gullies to cross, but nothing too challenging. On the descent, wrapping around the base of Pon-yama to join up with the campground access road, however, was a little more challenging. We dropped all the way down to the stream crossing around here, so had to side-step back up to the campground carpark.
From there it was a quick blat down the snowed-in road to the onsen.