Sun halo spotted over Portland Tuesday as temps warm
PORTLAND, Ore. (KOIN) -- Warmer spring-like temperatures have built over Portland Tuesday, but icy clouds have made for some fun atmospheric optics.
A 22° halo formed through the high, thin cirrus clouds above Portland Tuesday morning. Despite warmer than average temperatures felt at the surface, cirrus clouds are made up of ice crystals. It's those ice crystals that help refract the sun's rays into a halo. It's the 22° angle at which the light is bent that gives the halo its name.
Weather conditions high in the atmosphere have to be just right in regard to temperature and cloud thickness to allow this optical atmospheric event to to be seen overhead.