California Halos
An ice halo imaged at Laguna Beach, California by Scott Sporleder (scottsporleder photography). It disproves a commonly held belief that fine halo displays are only seen in polar regions or very cold weather.
 ©Scott Sporleder, shown with permission

Halos have their repeatable geometric forms because (1) ice crystals always have the same precise angles between their faces and (2) the crystals are precisely oriented in the sky.

Three crystal habits and at least four orientations are evident here.   

Randomly oriented crystals of unknown habit made the 22 degree circular halo.

Plate habit crystals oriented with their large hexagonal faces nearly horizontal produced the sundogs and colourful circumzenithal arc high above.

Column crystals drifting with their long axes almost horizontal made the gull-wing upper tangent arc and the rarer supralateral arc.

Parry oriented columns yielded the precise (and by eye) very colourful upper suncave Parry arc above the upper tangent arc.

.. at least four orientations are evident here?    The fifth? The ever hopeful eye and imagination might see Lowitz arcs joining the sundogs and the 22 degree halo. 


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