I climbed the classic west ridge of North Twin Sister Mountain near Mt. Baker on a fine August day. It was very warm and I got a late start. As many do, I used a mountain bike for the approach, which follows about nine kilometers of logging roads. The final part of this is an overgrown road that becomes a climbers’ trail. I left my bike at the trail.
I summited at 6:30 p.m. and downclimbed the fourth-class ridge safely while it was light, but it was dark when I got to my mountain bike. At this point, I was out of food and almost out of water, and was looking forward to the mostly downhill ride to the car. Although it occurred to me that my headlamp was poor illumination for downhill mountain biking, I got on the bike anyway. Within 200 meters I had an over-the-handlebars wipeout, breaking two ribs on my left side. After collecting myself and realizing I was not severely injured, and that my bike still worked, I cautiously and painfully rode out to my car.
As I was climbing alone (but within my ability and tolerance level for exposure), I took considerable care on the ascent and descent, but I let my guard down a bit once I started to hike out. This accident occurred on the descent, after all the major difficulties were behind me, which seems very typical of many mountain accidents and is why I am submitting this report. Also, many climbers occasionally use bikes for accessing the alpine. Riding in the dark when one is tired and on unfamiliar ground has risks that should not be underestimated, especially when alone. (Source: DG, male, age 56.)