I have hiked and biked through the tunnel many times, but this was the first time I hiked through and then over it.
The day was the warmest day we had seen in a few weeks -- temps in the 50s. The previous few weeks had been very cold which meant many beautiful ice sculptures in the "canyon" on the east end of the tunnel. One 6-foot section of the C&O Canal Trail was a sheet of ice, angled towards the canal! The kids in my group managed it just fine, but us "older" people were very worried about our balance. I ended up throwing a lot of debris (rocks, twigs, dirt) on the ice to give me more traction We all made it and everyone enjoyed the trail from the wonderful natural ice sculptures to the views from the top of the trail.