steer clear seems to be the best advice.
It’s one advice. Far from the best advice. Besides, you cannot really steer clear of them when flying over mountainous terrain. It’s a matter of learning how to rake advantage of the winds, not fighting them. Airliners take advantage of jet streams high up, VFR pilots can take advantage of waves.
To the IFR pilot who is expected to maintain altitude those waves are negative and strong turbulence.
As Neil and LeSving said, there will be no or negligible turbulence in the waves themselves (the dangers are in the rotors – avoid!), but maintaining altitude can be difficult for a light aircraft due to strong up- and downdrafts.
