The correct term for what you encountered is "wake turbulence" caused by wingtip vortices that are formed when a heavy aircraft flying at slower airspeed passes through the air....those little tornadoes contain contain high energy airflow that, once they leave the wingtip where they formed, tend to fall away and out from their source at around 500 feet per minute as they dissipate. So, in your experience, the crossing heavy aircraft was most likely configured for landing as it was descending about 1,000 feet above your altitude at a point about 2 minutes ahead of you on your flight path.....time enough for a pilot to maneuver to avoid that experience if only he had gotten the training to learn from his prior exposure and anticipate the invisible threat.......ask me how I know
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