In the US state of Colorado, a rare halo in the form of a dome was formed under the sun

In the south of the state of Colorado, USA, a rare meteorological phenomenon was observed: a solar halo in the form of a luminous dome above the horizon. The event was captured in Washington County, in the south of the state. Meteorologist Cory Reppenhagen shared the best footage of the incident on Twitter.

This phenomenon is called the "lower tangent arc". It is much rarer than the so-called "sun dogs", a type of halo. The dome-shaped halo is seen from 2 to 8 times a year.

In the video, you can see ice crystals floating in the air, which cause this impressive optical illusion. This requires a suitable shape and location of the crystals in relation to the sun in the sky.

According to the information Ice-halo.net, columnar crystals in the form of regular hexagonal rods refract the rays in the right way. The sun should be high enough, at sunset, the lower arc is not visible, as it is hidden behind the horizon.

When the sun is more than 35 degrees above the horizon, the upper and lower tangent arcs combine to form an encircling halo.