First, configure the inside of your mouth to say the word “who”.  

Now drop the back of your tongue (the part that goes down your throat) down into your lower jaw so that you produce a large, resonant cavity in your mouth.   Exhale forcefully but slowly from deep in your diaphragm, like the air leaking from an old tire. You are pushing an entire column of air out your mouth.

If you’ve done this correctly, you will have produced a low, sustained, howling sound very similar to the sound that the wind is making outside my window on this cold January night.  The wind is creating a hollow, almost subsonic, rumbling that is everywhere.  It is eerie, like a moving atmospheric train… which is exactly what it is.  But when you look out the window, the branches are barely moving, and when you go outside, you notice that the sound seems to be starting from the top of the trees – up where the branches become finer and finer until they terminate in tiny buds.  It starts up there, but eventually it comes from… everywhere.

From my warm basement, it occurs to me that, on this night at least, the wind isn’t blowing – the air is moving.  There’s a difference.  Wind is caused by differences in atmospheric pressure.  High pressure is always moving outwards to fill in the spaces while low pressure invites air to move towards it and fill the void.  The greater the pressure difference, the harder the wind blows.

The coldest air of the winter so far is blowing down from central Canada tonight.  (The coldest air always comes from central Canada.  It makes you wonder what the planet is doing up there to make it so cold.)  But even though there are pressure differences involved, this is your basic air mass run amuck.  This is a huge, viscous ooze of cold, arctic air that is spreading south like pancake batter oozing across a baking pan.  It is relentless and unstoppable.  It couldn’t stop if it wanted to… there is just too much cold air piled up behind it.  This isn’t wind, this is the atmosphere moving en masse.

That explains the lack of movement in the trees.  The wind isn’t gusting and swirling and eddying, it is moving as one.  Watch the leaves as they blow along the ground, they don’t stop and start, they move steadily in one direction.  They enter the picture, they pass through the picture, they pass out of the picture. The air mass is not concerned with “here”, it is only concerned with “there”.  I and my little house just happen to be in its path.

And that also explains the whistles and shrieks that come from around my window and under my door.  When it’s just the wind blowing, the wind bounces off my house and recoils to swirl the leaves and rustle the trees. But tonight the atmosphere is being squeezed like toothpaste and in places little tiny shreds of it are being forced through the tiniest cracks where they are ripped off and isolated from the main body.

Tiny, frightened shreds of cold Canadian air in a warm Pennsylvania basement.

Their little voices howl in protest.