Originally Posted by
woodpecker
A few years back, during a very smooth Atlantic crossing, someone (never did find out his callsign) on the chat frequency was asking for ride reports at 36000' having just passed 30W. All the responses were "smooth ride" all the way across. One American pilot, who it would seem had worked out that he was two minutes ahead of this traffic and at 37000' on the same track suggested perhaps he was sitting in his wake turbulence (remember vortices descend at about 500'/min).
Contrails don't descend much, if at all.
I've had to offset slightly to avoid turbulence from contrails. Offset out of the contrail and the ride improved immediately.