> there are big piles of rocks waiting to stop you uncomfortably at the bottom if you are unable to stop yourself

That's the understatement of the day. People die when they hit those rocks.

Looking at the late Wayne Pyle's 99 switchbacks diagram, the slope drops about a thousand feet, maybe 1200. Slopes always seem steeper than they really are. I don't think it is 45 degrees. Not sure if anyone has measured it.