Snow sky.

Before I went on my anti-winter, anti-ice screed last week I mentioned that winter in the north does have some peculiar qualities that make it quite fascinating. These are things I have come to admire more since we started collecting dogs, since my previous opinion of the outdoors was as "a place to be between being indoors" and "the locale of interminable chores." You wind up spending a lot more time outside with dogs.

One of the things I've always been in awe of is the snow sky -- when it's snowing, or about to be, the sky is overall lit up in white, almost bright as day. It's a cool sort of brightness, unlike sunshine, and since it seems to come from everywhere, shadows are not pronounced.

I was not able to get a good picture during our last snowstorm...

You can get some idea of the scene early the next morning, but the sun was coming up:

I used to think it was diffused moonlight, but apparently it's the same whether there's a full moon or no moon. Apparently it is an effect of skyglow, a term I had not previously heard. Skyglow sounds like a photon-powered superheroine from the seventies, or Twilight fan fiction, or possibly a roller disco, or maybe the worst James Bond movie ever.

Here's Dr. Wikipedia on the subject:

Skyglow (or sky glow) is the diffuse luminance of the night sky, apart from discrete light sources such as the Moon and visible individual stars. It is a commonly noticed aspect of light pollution.... Skyglow is significantly amplified by the presence of snow, and within and near urban areas when clouds are present. In remote areas snow brightens the sky, but clouds make the sky darker.

This would seem to indicate that the snow sky I describe was unknown before electrification. Funny that I seldom noted it while living in the city, but here in the burbs, where there's a lot less public light, I see it often. Also, dogs.

However, the snow sky may be less related to electrification of cities than the above article would make us think. Sky & Telescope, a publication about astronomy, notes:

Even a completely unpolluted sky is surprisingly bright, illuminating the ground enough for you to walk quite confidently through an open field. More than 90% of natural skyglow comes from three sources: the zodiacal light, upper-atmosphere airglow, and starlight.

And:

Fresh snow increases skyglow several-fold. You can even see this effect during broad daylight. Although the air is often very clear right after a storm, the sky is visibly whiter than usual because of all the sunlight reflected back into the sky. Artificial skyglow at night decreases rapidly as snow is cleared out of parking lots and from underneath streetlights, and then continues to decline more slowly as the snow becomes dirty.

It's a pretty wild effect anyway. I find when I'm outside at night and it's snowing and the sky is white with a mellow glow, it's almost cozy. It is cold and wet by definition, but there's a blanket above as well as a blanket below. It is something I would miss about winter if I ever smarten up and move south.