Some…yeah, where some is the 1.7 million cubic yards of rubble now clogging up the Thermalito Diversion Pool. [1]
When you look at photos or drone videos of the erosion near the main spillway, it's clear that an immense amount of rock has been eroded away (the color changes from brown to gray). [2]
Juan Browne discusses the type and strength of the rock in one of his excellent videos about the Oroville crisis. [3] (Note that he demonstrates the weakness of the rock where he is standing, which is across the river from the spillway and might not be the same rock.)
When you look at photos or drone videos of the erosion near the main spillway, it's clear that an immense amount of rock has been eroded away (the color changes from brown to gray). [2]
Juan Browne discusses the type and strength of the rock in one of his excellent videos about the Oroville crisis. [3] (Note that he demonstrates the weakness of the rock where he is standing, which is across the river from the spillway and might not be the same rock.)
[1] http://www.mercurynews.com/2017/03/03/spoil-sites-for-orovil...
[2] https://www.youtube.com/watch?v=TpXtMZwpDqs
[3] https://youtu.be/ilkU_ivYTqQ?t=679