As AerocatS2A says you were probaly in the downward portion of a wave, but, as you are quoting " turbulence" I would rather think that you were in a rotor (i.e. lower lever part of the wave system), which makes you even luckier (not a place to be unknowingly)
Introduction to leevawes & rotors
to follow JEP's tracks, a bit more info about location vs mountain systems w/r to wind and cruising altitude would make it even easier to make "qualified guesses"