This rock fall sounded like a clap of thunder, except it was more like a crack of thunder. I actually had time to run into my house for my camera and back out and still see tumbling blocks. Pretty awesome.
I have a photo taken from near the base of the Priest showing the Porcupine Rim. It shows a light dusting of snow that happened the day before along with a huge red rock dust stain that must have been the result of a similar event. I will see if I can track it down.