We’ve certainly had our share (more than our share!) of snowstorms and blizzards so far this winter, though nothing like people down east have experienced. The one saving grace is that after the storm the sky often clears beautifully. In this case, on January 30, 2011 we had very clear blue skies, but filled with ice crystals of just the right shape (hexagonal) and orientation to produce a classic solar halo, with prominent sundogs on the 22° halo and a hint of an upper tangent arc, or is it an upper Parry arc? A trace of a circumhorizontal arc is also visible parallel to the horizon. Solar haloes are fascinating and often unique — each one can display a slightly different set of halo phenomena.
The website Atmospheric Optics gives great information and reference works.
– Alan, January 2011 / Image © 2011 Alan Dyer
The Amazing Sky 