Yes, water is a very excellent RF attenuator at all frequencies. Acoustic waves travel quite far in water, especially in the ~1 kHz range. Making loud sounds

Yes, water is a very excellent RF attenuator at all frequencies. Acoustic waves travel quite far in water, especially in the ~1 kHz range. Making loud sounds isn't something you want to do when you're somewhere you're not supposed to be though. If a mountain isn't making any noise then it's going to be difficult to know that it's there.