Comments

  1. Saad says

    I looked up the weather up there out of curiosity…. -8???

    I like winter but damn…

    It’s 63 here down in Jawja. I wish we actually had a winter here.

  2. Dunc says

    I looked up the weather up there out of curiosity…. -8???

    Pretty cold, but not that extreme…

    It’s 63 here down in Jawja. I wish we actually had a winter here.

    Oh shit, you’re using Fahrenheit… OK, -8 F really is cold.

  3. Bruce Fuentes says

    We hit a low of about -10F (-23C) last night. Still below 0F. -1F (-18C) currently. Time to go out and move some snow.

  4. says

    -8 is getting there. Once has to pull a car battery because the seatbelt dangling kept the door open and drained the battery. It was -17 during the day in the Twin Cities.

  5. blf says

    It’s about 9 here in the evening, expecting to drop down to about 7 during the night. ℃, that is. Will probably have carry a sweater if I go out for dinner.

  6. unclefrogy says

    well that is why I do not live in the north or the mountains! that is colder than my freezer gets.
    It does get chilly here down in L.A. and people do complain of cold but damn.
    having never seen anything like that I thought it was an artifact of the camera you, say that that is an effect of freezing water vapor?
    what I notice about the seasonal change mostly is the changing color of the light do to the angle of the sun.
    uncle frogy

  7. Rob Grigjanis says

    unclefrogy @12: Yeah, it’s about light refracting through hexagonal ice crystals. There’s a wide range of incident angles which result in a roughly 22 degree deflection*, which is why (with crystals randomly oriented about their central axis) you see a halo at 22 degrees away from the sun. The sun dogs (bright patches either side of the sun) are a result of plate-like crystals being largely horizontally oriented (vertical central axis).

    *See interactive ray diagram here.

  8. Hj Hornbeck says

    I am deeply impressed to see people posting high-level technical explanations of sun dogs. I’ve had a brief look into them for my academic work, and more-or-less ran away due to the ridiculously complex scattering that results. From ice! A crystal formed from a three-atom molecule!

  9. methuseus says

    I miss northern winters. It’s currently 85 here today. Later in the week it’ll be down to around freezing at night, but still 55-60 during the day. People still pull out parkas anytime the temp gets down below 60, though. I still sometimes wear shorts.

  10. gijoel says

    I’m currently in Brisbane where it’s 34c (93f). Also the sky is white due to the large amount of bushfire ash in the air. I’d kill any deity of your choice to stop this awful weather.

  11. birgerjohansson says

    Rob Grigjanis @ 14, Hj Hornbeck @ 15
    -Something even more mysterious are the vertical columns of light you sometimes see rising up from light sources on cold winter nights. Random light scattering should result in halos or rings.
    It is as if the ice crystals magically “know” the vertical axis and deflect light by 90 degrees.
    Since the crystals are so small they basically hover in the air, there is no aerodynamic force resulting from falling vertically and affecting their spatial orientation.
    Sound waves are refracted sideways by the temperature inversions near the ground in winter, but temperature inversions cannot affect the orientation of ice crystals. So what is happening?

  12. Rob Grigjanis says

    birgerjohansson @21: The plate-like crystals I mentioned in #14 are oriented roughly horizontally as they slowly descend. The light you see doesn’t come from directly above the source. It is reflected from the bottoms of crystals between, and above, you and the source. So the column is an optical illusion.

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