G1/G1 Remake: What is the source of the "Yon Waay..." mountain sound effect?

In both the original and the remake, I've always wondered what sound library a certain effect comes from when you are in the mountainous/elevated part of the colony. (For example, the Orc Citadel where Ur-Shak is).

It almost sounds vocal. Like a person is saying "Yon waay, Yon wayy", etc. but with a notable reverb and echo.