Originally Posted by retinax
Would that be because for the green and red pixels, it's a low light situation?
Yes. Blue clips first.
Bright cloud regions can clip too. Pure white means equal amount of R, G and B. But if those regions are bright and white, low-level clipping with CMOS sensors is harmless (clipped regions render as white!). As overexposure increases, CCD sensors will exhibit blooming artifacts well before CMOS sensors.