Wednesday, November 10, 2010

Freezing Rain in Vermont, Autumn in Pittsburgh's Urban Ecosystems




I'm fairly familiar with the mechanism by which freezing rain occurs.  Warm air is pushed over below-freezing air, but cold air remains trapped beneath it, especially in valleys and hollows.  As is often the case with the changing of air masses, rain also occurs.  If the rain goes through enough cold air to freeze, it becomes sleet - basically frozen raindrops.  However, if the layer of cold air is thin, the rain may not freeze until it hits something - a tree branch, perhaps, or a metal sign, or a roadway... apparently even metal trash cans.
What I was not familiar with was what it was LIKE to be outside during freezing rain.  I'm not sure if it was because there was also some sleet, or if it was because the raindrops were hitting branches and leaves covered in ice, but freezing rain SOUNDS very different from normal rain.  In addition to normal rainy 'bloops' and splashing sounds, there were sharp, tinkling noises, almost like a tiny bell ringing with each raindrop.  The effect was subtle but was quite noticeable when standing near a plant.  The rain itself was biting, due to small pieces of sleet mixing in, but otherwise didn't feel that much colder than the 38 degree rain I experienced a few weeks ago during that big nor'easter.  The grass was, for an hour or so, coated with a thin layer of ice.  In Burlington, the temperatures were barely cold enough for freezing rain, so the roads and walkways were mostly ice-free.  This wasn't the case in other parts of Vermont, where there were some accidents.  Large amounts of freezing rain can also rip down tree branches and powerlines, but in this case, there wasn't nearly enough accumulation for that to happen.



The ice didn't stick around in Burlington, but in many parts of the state there was accumulation of slushy snow, sleet, and ice.  Middlebury had an inch or two of sad-looking snow, and around Richmond there was still a bit of ice and snow around.
This snow had the consistency of quinoa.

For more information on this storm in Vermont, check out the Burlington Free Press weather blog entry about it.

Meanwhile, in Pittsburgh, the fall color season is mostly over (it has been over in Vermont for several weeks.).  You can re-live this season's beautiful fall foliage though, by checking out this entry in the Pittsburgh Parks Conservancy blog.  Melissa McMasters has taken some beautiful photos of the fall leaf season in Pittsburgh.  One very neat thing about these photos is that all of them were taken in urban parks within the Pittsburgh city limits!  Pittsburgh is truly lucky to have such beautiful parks in locations where so many people are able to enjoy them!  The leaves may be gone but any day in the park will have something new and beautiful to see... so make sure to set some time to enjoy nature, even if you're in the city.

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