If you’ve recently seen an moon with angels appearing in two area skies, there’s an interesting scientific reason for celestial vision.
Jain Nale, a meteorologist at Golden Gate Weather Services, posted on Twitter on Saturday, “Light from almost the full moon is interrupted this evening by ice crystals in thin circus clouds over the bay area.”
Although noticeable to look at, haloes are actually more common than rainbows.
The moon haloes when there are high, thin clouds in the sky. The clouds are filled with numerous ice crystals, each of which is shaped like a small hexagon. Crystals, like a million small lighthouses, remove light through each. Light decreases by 22 degrees, which is the radius of the lunar halo.
The event is both visible during the day and at night, and residents of the two areas were lucky to experience it on Saturday night.
Thin clouds are likely to be replaced by stormy clouds the following Sunday. The bay area is expected to receive some rain overnight, and it is so cold that snow is possible at higher altitudes.
“Due to the temps expected to freeze near / near from 4000 feet above, some high altitudes are likely to see a slight accumulation of ice!” The Bay Area National Weather Service Office tweeted Sunday morning. “We’ll keep an eye on the Santa Lucia and Diablo ranges tonight.”
