Crystal clear

Hi,
These are frost crystals on black ice on Lake Superior.  I don't know how they have formed, because it has been sooo cold lately. I wouldn't have thought that the air had any moisture in it to give up.  Also, the crystals seem to be pointing away from the direction of the prevailing winds. More questions than answers.

I took my first walk since last year on Superior's ice.  It was eery, (not Erie) as the ice was making weird noises, and there was open water about a km away.  But it has been -30 C or below on many nights lately; so I figured it would be safe.  Anyway, I stayed close to shore.  There was some completely clear ice. Only by looking at the cracks can you get an idea of the thickness of the ice.