Scio - in all probability the figures were instantaneous (or even 'max' for effect....) and not sustained.
Plank says sorry to rotary man - I read your post as assuming the wind had anything to do with the altitude 'lows'. It didn't really.
TBsix - this event has shocked me and probably quite a few other current and ex pilots. I have always held RY training and supervision in high regard considering the intensity and pressures that the crews operate under, but this (September event) has just blown my mind.
It is interesting seeing the addenda coming into the AvHerald report.