-> Actually, it may be due to a lack of anything credible these days. 
  
Here's something that mystifies me. We've had a lot of snow here of 
late. Sometimes, aircraft can be heard flying above, or maybe through, 
the snow clouds. When this happens, the sound of the engines gets 
altered, something like the "phasing" effect that pop musicians used to 
like to use. The direction from which the sound comes also seems to be 
highly variable, sometimes shifting dramatically very fast. The overall 
effect suggests that sound is getting bounced around somehow. 
  
But how? And in what way are snow clouds able to do this but not 
regular clouds? 
  
                           dow 
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