The Storm Team Weather office received several calls Monday evening from people who reported seeing a "perfect circle" or a ring of light around the nighttime moon, a sight that was unfamiliar to them.
The halo is caused by the presence of tiny ice crystals in the upper atmosphere. The reflected light off the surface of the moon is then refracted -- or bent -- as the light shines through the ice crystals. This natural physical process continues for as long as the ice crystals and light source are present, resulting in the vision of the halo around the moon.
Most of the region experienced high, thin cirrus cloudiness for most of Monday and continued into Tuesday morning. These cirrus clouds are made mainly of ice crystals, which are contributing to the creation of the circle around the moon.
