Possibly as large as the one that took out Happy Isles a few year's back. A large crack has formed and is widening.
I vacationed in Yosemite every summer of my life thru college. There was never a night that went by that a rock would not fall... breaking loose from a cliff side or being swept over a waterfall... and cracking like a bomb when it hit... echoing thru the valley for what seemed like minutes. I have witnessed a few, nothing really major. The day after I first hiked to the top of Yosemite Falls a rock slide took out the trail and killed some people, 2 I think. Rocks falls are very common. True rock slides not so much, but not rare either.
By far 'water', (The Merced River), is the most dangerous thing that befalls visitors. There is no shortage of danger in Yosemite. - JamesJM
