We parked alongside the bridge to take some photos of some big horn sheep ended up in the middle of a bison stampede. We were standing behind our SUV and we had bison coming across the street and down the hill alongside of us. Three of our group had to jump in the back of the suburban as the bison ran past. There must have been around 250-300 bison. Our guide said it was the biggest group he had experienced that close. Most of them crossed the bridge but some of them crossed the river. What an experience.