I LOVE Powell, my home land, raised there most my life.
I see a lot of rock slabs that look like they ought to fall some day, but i never have SEEN one fall in my life... naturally anyway ;). Deffinately bad luck... I wonder if the park service will knock over potential threats (rocks) after this, kind of how avalanches are purposely caused in some mountainous regions for safety. I bet they wont though, since it is such a freak accident, and since it would be "un-natural" to purposely knock off boulders and slabs
My friends and i pushed one off a cliff in the dessert nearly a mile from my home. though the slab was only about 10ft x 4ft x 4ft or so, the rock made a loud enough noise that my dad heard it from the house and rushed out on the 3-wheeler to check up on us. (it probably took 2 hours to push it off too)... i look back on it now with stupidity, especially in light of this incidence (... but it still is a "fun" memory...)