14 November 2012

Three weeks ago I wrote about radiation fog and inversions.  We had another inversion recently, this time without fog.

Here is the view last Sunday from the Allegheny Front Hawk Watch.  It looks like a bad picture of beautiful scenery but it’s actually a good illustration of a hazy inversion.  Notice how the near trees are colorful and Wills Mountain, 10.5 miles away,  is bland and washed out.  You can’t see the fire tower on Kinton Knob.  The colors are cancelled by bad air.

This was a classic temperature inversion but the first time I was able to measure it.  As I drove to the hawk watch my car’s outdoor thermometer registered 43^o in the Laurel Highland valleys and 57^o on top of the mountain.  Normally the hawk watch site is far colder than anywhere else in western PA.

The weather was topsy-turvy.  Warm air aloft trapped cold air below and with it pollutants that made the air smell bad in the cold zones.

Bad air was not limited to cities and industrial zones.  On my way to the Allegheny Front I saw quite a few outdoor wood boilers creating thick white smoke that blanketed rural areas.  These relatively new devices burn wood in backyard sheds to heat water for radiators in homes.  Because outdoor wood boilers are small scale polluters they weren’t on the bad air radar at first, but their smoke is much worse than typical burning because the fire smolders when indoor heat demand is low.  I saw valleys where wood smoke enveloped nearby homes and neighbors.

At the hawk watch the air was nice and warm.

So when there’s an inversion, go to the mountain.

(photo by Kate St. John)