I don't know this case, but there were many cases before that: 1. No, in most cases it is CAT (clear air turbulence). CB turbulence is easily detected by radar

I don't know this case, but there were many cases before that: 1. No, in most cases it is CAT (clear air turbulence). CB turbulence is easily detected by radar and avoided; CAT doesn't show on radar as there are no clouds involved. 2. No, since it comes without a warning. I mean there are forecasts of CAT, and you also hear what other aircraft report (the ATC takes that into account too), but every now and then someone has to be the first to enter some more shaky air. Also, in most cases this is at best moderate turbulence (meaning it doesn't really affect the handling of the plane), but that is enough to temporarily get from 1g to 0g or below, and make some passenger fly up in the cabin, then fall down.