December 28, 2012 Winter Time at the Tree of Doom…and Fallstreak Holes

We had a brief respite from wet weather on Friday, December 28, and the afternoon air was crystal clear with some very nice altocumulus clouds above.  This was a great day to try out my new Zeiss 21mm lens at the Tree of Doom in Schoolhouse Canyon.

I suppose the pictures can do the talking — who wants to read 12,000 words anyway?

I should say a word or two about the giant holes in the altocumulus field.  These are called “fallstreak holes”, or “hole-punch clouds”.  Google “fallstreak hole” to learn more about these.  Images 9584 shows three of these lined up to the south, and later 9592 shows three lined up to the north.  (I am fairly certain that these are not the same set of three holes!)  It is thought by some that jet aircraft which pass near or through these mid-to-upper level clouds cause liquid water droplets to suddenly freeze, causing this local upper-level virga snow shower (or “fallstreak”).  Perhaps there was a “hotspot” upstream where an active jetliner corridor intersected the altocumulus field.  As each jet  passed through, a hole and fallstreak developed.  These holes would move NNE on the upper winds, and a fresh, untouched altocumulus field awaited the next jetliner, and so on.