Years ago when I was a kid, maybe 1950, we camped in Yellowstone Park. We slept on the ground in sleeping bags and in the night we were awakened by growling. There was a momma bear and her cub right in the middle of our group and she was scolding her cub. It could have been tragic.
We did see some very large bears by the highway about four years ago while crossing the Rockies from Alberta to B.C. They could have been grizzlies. I didn't get out of the car to make sure.