You have to understand the nature of the terrain in the area he was hunting. He was going downhill, and met the bear which was proceeding uphill. I don't know exactly which mountain he was on, but the undergrowth likely consisted of rhododendron and kalmia (mountain laurel and ivy). These thickets are referred to as "rhododendron hells" and "swimming laurel". The sight distance in an area such as this is measured in feet, not yards.

So, he might have encountered the bear at a range of 10 to 15 feet. He was fortunate the bear only swiped at him one time.