Low Rumbling Noise

Treetopleaf
Fri, 04 Feb 2011 09:52:35 +0000

I vote for the helicopter too. Was it cloudy? That can affect the quality of the sounds you hear. And when the helicopter moves off a bit, the sound can completely disappear.

Or it could have been a snowblower, or a tree chipper. Once I heard a really strange droning sound and looked up to see a blimp!