Tuesday, January 7, 2014

Frost Quakes or Cold Booms

A few years ago we moved to Northern Virginia from Texas. We told the winters were mild. Perhaps we'd get a couple of inches of snow. There might be a couple of ice storms.  And that would be that.  Since moving here I have experienced life in the Arctic!  Our first winter amassed over 50" of snow! A typical winter morning can be in the teens.  The wind chill can be fierce. Since moving here I've started a collection of Under Armour, wool socks, wool sweaters, boots, hand warmers and toe warmers, none of which I owned in Texas!


Last week was interesting, and now a bit of a blur.  We were told we wouldn't get much snow on Thursday afternoon (was that Thursday), then suddenly we were expecting 1-3." Night fell to a lovely picture of falling snow. We awoke Friday to a winter wonderland. We got almost 2" of snow that was fluffy enough to look pretty.  A slow thaw allowed snow cover to tenaciously held on through a bitterly cold, below freezing, Sunday night. Monday morning I opened the blinds to a warm 40 degrees with hardly any snow in sight! What happened?  That was the warmest part of the day, as temperatures fell in preparation for...the polar vortex.    


Now I know that a polar vortex can play hooky from the North Pole to vacation in America. Mysteriously though, the eery and powerfully noisy explosions arrived as well.  Three different nights this week I've heard what seems to be muffled gun shots...or was that a cannon booming under the house?  Sometimes the explosion is so fierce that it shakes the house!  Listening to these sounds, at night, when I'm alone and up late preparing lessons, is a bit rattling to my nerves as well as the house.


Last night I mentioned this on facebook and a friend in Ohio has been hearing the same noises.  After I closed up facebook and went to bed, she saw someone posting an article from Toronto on frostquakes that she shared on my timeline. Scientifically called "cryoseisms," these "explosions" are caused by the expansion of water in the ground when the temperature falls drastically.  That certainly happened around here with temps ranging from the 40's to a record setting 1 degree.


After hearing more explosions this morning, I contacted Capital Weather Gang via facebook to comment about it.  Alas, they never replied.  Tonight I was catching up on facebook and saw that CWG posted the following link about cryoseisms about three hours after I submitted my info!  Apparently another name for "frost quake" is "cold boom," since these sound almost like sonic booms.  I have heard a sonic boom when I lived in on Sheppard AFB in Texas, home to the NATO pilot program.  Yes, I agreed, a boom is another good name for these explosions! I was especially interested in the comments. At last there was confirmation that many neighbors in NoVa have also heard these explosions!  


CWG defines cryoseism as "a mini-explosion within the ground caused by the rapid expansion of frozen water." They say this is rare in the lower lattitudes, but then, so are polar vortexes!


Since moving to NoVA, I have experienced multiple blizzards in one winter, a derecho, an earthquake, a hybrid hurricane clashing with a northeaster, a polar vortex and frost quakes! I think that's enough adventure!

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