Tuesday, July 23, 2013

Circumzenithal Arc

We don't know when the deserts of California started having monsoon rains, but they do in the summer now. When the pressure system is right, thunderstorms roll up the Sierra mountains creating as many as 7300 lightning strikes in one night.

Monday night was like that. We didn't see any lightning here, but the clouds rolled in Monday afternoon, cooling down our 97+ degree scorcher and providing us with much needed relief. Sierra skies are so typically cloudless in the summer that when clouds do show up, we have to go outside just to see what splendid things are happening up there.

After dinner I walked out on the deck and looked at the western sky. The sun was already behind the hills, and I saw my first circumzenithal arc. And thanks to Atmospheric Optics, I knew what it was as soon as I saw it.  Sights like this don't last very long. It's that ephemeral quality that makes it so beautiful.

One of the things I have been wondering, now that we are planning to sell the house next spring, is how much of what we see in the sky is particular to the skies here. Is it the elevation (2600 ft), or the proximity to a mountain range, or being on the western slope where weather systems stall? Or, is it that we have enough free time and attention to see the things that are normally fleeting and ephemeral? What do you think? I know a lot of people say that they don't see skies like this, but why is that true?




11 comments:

  1. We only have 18 hours of daylight now, but still plenty of beautiful sky. They have been blue more this summer than any in the almost 30 years I've lived her. We could use a little gray skies and rainthough.

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  2. I don't see skies like this mostly because I don't look up enuf, and I suspect that's the reason many others don't as well. Plus, I'm not as educated as you to know when to look, what to look for, or even when I might be seeing something special or unique.

    One of the fascinating things about being human, though, is that I can change all of that.

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  3. I think Pablo is right. The main reason you see so much neat stuff in the sky is that you're paying attention. Most people don't notice even the most dramatic displays. A lot of people never saw that tremendous display in the sky over Huntsville a while back (the one I linked to). I wonder if you move to the coast if you'll be able to see the green flash. I saw it once many years ago when I was passing through Hawaii on business. I keep looking, but I have never seen it again.

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  4. I agree with the others. We simply don't look up often enough. That's why we got a recliner for the deck. It encourages us to look beyond the trees.

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  5. Robin Andrea: I've never heard of (or seen) a circumzenithal arc; thanks for enlightening and edifying me. I don't know enough about atmospheric properties to weigh in on why you see so many rainbow-hued celestial phenomena, but I think that I look up enough (searching for birds) to know that, if such apparitions appeared frequently here in Mid-Atlantic skies, I'd see them once in a while--which I don't. I think you've got some special conditions there that you can enjoy for a few more moths anyway.

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  6. These types of things are most often visible when the sun is fairly low and there are high, thin clouds. If the clouds are too thick, the light doesn't get through. If the clouds are too thin, the arcs and halos are so faint they may be hard to see. Down South, good conditions often occur when a cold front is approaching, so we usually see more of them in cooler/colder parts of the year, but they can happen any time. If I notice high, thin clouds late in the day, I start looking for sun dogs.

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  7. Every place has its own special gift. Never would have thought there would be so much rainbow play of light in the sky on the western slope of the Sierra Nevada. I treasure your photos from the places that you and roger have made your home and really taken a good look around.

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  8. An upside down rainbow??I had no idea they existed. You always manage to see and photograph some marvelous sky scenes. I do look up a lot and have never seen what you do. Think it is where you are. Keep taking those pictures for those of us with less dramatic skies.

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  9. Nice captures, your lens and eyes!

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  10. Hi there! Long time...
    I was looking through some books this morning and saw a copy of Dharma Bums. Although I've read the book before, that isn't what popped into my mind. Your blog is what I thought of and it made me wonder why I never see new blog posts by you pop up on my reader. Then I saw that your blog isn't on my reader anymore. I have no idea what happened and it makes me wonder how many others are missing.

    Anyway, I just added to my list and hope it stays there. I plan on catching up.

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  11. And now to the actual post...
    I've been in and around the SoCal deserts for most of my life. As far back as I can remember, there has been a monsoon effect in the deserts down here. The desert isn't much fun when it's hot AND humid.

    I don't think I've been lucky enough to see one of those arcs before, but I'm going to keep my eyes open for them now! Thanks!

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