OPOD - California Halos

Last updated on September 16, 2023

OPOD - California Halos: Exploring the Mysteries of Ice Crystals in the Sky

When we think of ice halos and their mesmerizing displays, our minds often conjure images of polar regions or extremely cold weather. However, a stunning photograph captured by Scott Sporleder at Laguna Beach, California, challenges this commonly held belief. The image showcases an ice halo in all its glory, dispelling the notion that these fine halo displays are exclusive to specific regions or frigid temperatures.

Ice halos possess their distinct geometric forms due to two key factors: the precise angles between the faces of ice crystals and their precise orientation in the sky. In the photograph, we can observe three crystal habits and at least four orientations, revealing the complexity and diversity of these atmospheric phenomena.

Let's delve deeper into the captivating details of this photograph and unravel the mysteries of California halos:

Crystal Habits and Orientations

1. 22 Degree Circular Halo: Randomly oriented crystals of unknown habit create this circular halo, spanning 22 degrees around the sun or moon. Its appearance is a result of sunlight or moonlight refracting through the ice crystals at a specific angle.

2. Sundogs and Colorful Circumzenithal Arc: Plate habit crystals with their large hexagonal faces almost horizontal generate the mesmerizing sundogs and the vibrant circumzenithal arc high above. Sundogs are bright spots on either side of the sun, caused by the refraction of sunlight through these oriented crystals.

3. Gull-Wing Upper Tangent Arc and Supralateral Arc: Column crystals drifting with their long axes nearly horizontal form the gull-wing upper tangent arc and the rarer supralateral arc. These arcs appear above and parallel to the main 22-degree halo, adding a touch of elegance to the atmospheric display.

4. Upper Suncave Parry Arc: Parry-oriented columns contribute to the formation of the precise and vivid upper suncave Parry arc, positioned above the upper tangent arc. The interplay of sunlight with these specialized crystals produces an enchanting array of colors.

5. Potential Lowitz Arcs: With an ever hopeful eye and vivid imagination, one might spot Lowitz arcs connecting the sundogs and the 22-degree halo. However, their presence in this particular photograph is not confirmed.

The Fascinating World of Ice Halos

Ice halos are not limited to polar regions or extremely cold weather. They can manifest in various locations, surprising us with their ethereal beauty. While California may not be synonymous with icy landscapes, the presence of ice crystals in the atmosphere can still create these captivating optical phenomena.

The precise angles between the faces of ice crystals play a crucial role in determining the shape and size of halos. Whether it's the 22-degree circular halo or the intricate arcs and spots observed in the photograph, each phenomenon arises from the interaction between sunlight or moonlight and these perfectly aligned ice crystals.

Ice crystals exhibit different habits and orientations, leading to a diverse range of halo formations. The random orientation of crystals of unknown habit generates the circular halo, while plate habit crystals with their large hexagonal faces nearly horizontal give rise to sundogs and the colorful circumzenithal arc.

Column crystals, drifting with their long axes almost horizontal, contribute to the creation of the gull-wing upper tangent arc and the rarer supralateral arc. These arcs appear parallel to the main halo, adding an extra layer of complexity to the atmospheric display.

The unique Parry orientation of column crystals yields the precise and visually striking upper suncave Parry arc positioned above the upper tangent arc. The interplay between sunlight and these specialized crystals produces a vivid array of colors, enhancing the overall enchantment of the halo display.

Although not confirmed in this particular photograph, one might also imagine the presence of Lowitz arcs connecting the sundogs and the 22-degree halo. These arcs, if observed, would further elevate the visual spectacle.

In conclusion, the photograph of the ice halo captured in Laguna Beach, California, challenges our preconceived notions about the geographical limitations of these atmospheric phenomena. It reminds us that nature's wonders are not confined to specific regions but can manifest unexpectedly, captivating our senses and inspiring awe. The intricate interplay between ice crystals and light creates a symphony of colors and shapes, reminding us of the beauty and complexity that exists within our atmosphere. So, keep your eyes open and your imagination alive, for you never know when you might witness the magic of a halo display, even in the most unexpected of places.

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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