Supralateral arc:<\/strong> This arc is tangent to the 46\u00b0 halo with which it is often confused. It touches the circumzenithal arc but is curved down. This is caused by the refraction of the sunlight through the 90\u00b0 edges of the oriented columns. It is quite bright in this picture and its centre approximately on the sun.<\/p>\n Upper tangential arc<\/strong>: The optical phenomena in the lower portion of the picture appears separate, but is caused by the same types of crystals. The upper one appearing like a graceful bird’s wings is the upper tangential arc. This is caused by the refraction of the sunlight through the 120\u00b0 edges of the oriented columns. The 120\u00b0 is accomplished by light passing through alternate sides of those separated by 60\u00b0. This arc evolves quickly depending upon the sun’s height.<\/p>\n 22\u00b0 halo<\/strong>: This is the most common of all the phenomena. It is located at an angle of 22\u00b0 from the sun. Like the others, it is the result of refraction but of randomly-oriented small plates or columns. It is caused by refraction though 120\u00b0 prisms.<\/p>\n A halo complex usually presages rain. <\/p>\n","protected":false},"excerpt":{"rendered":" On Tuesday, there was overrunning of cirrus over the Lake. On Wednesday, there was rain. Lorraine Symmes took a picture to the west and sent it to me. It showed a halo complex, something that often precedes rain. All … Continue reading
\n![\"\"](\"https:\/\/blog.kootenay-lake.ca\/wp-content\/uploads\/2022\/05\/halocomplex220403BG.jpg\")
\nPhotograph courtesy Lorraine Symmes.<\/p>\n