Horsehead Arch Rock Climbing

Horsehead Arch is a ~160-foot tall granite arch high on south side of Blodgett Canyon. The arch can be seen from trail just before the main trail crosses the creek at a bridge.

Geology lesson: I have a friend who was a geology professor for over 30 years. I asked him how an arch like Horsehead Arch formed. Here was his response: "How it formed....arches in granitic rock usually form by a favorable set of joints that allow progressive collapse of blocks once an opening occurs below while maintaining enough rock to be self- supporting. Obviously arches eventually collapse, and one that has evolved to the thinness and apparent delicacy of Horsehead is doomed, perhaps a week from next Tuesday! The final cause of failure will most likely be a bit more ice wedging in cracks, or less likely, an earthquake, which do occur in Montana (1959, near Yellowstone, magnitude 7.1). Or maybe two really stout climbers."