I was on Portland’s east side when I turned a corner and there it was: a faint halo or ‘ring around the sun’ with a big bright spot on top.
That bright light is called a ‘tangent arc’ and if it’s going to form, it’ll be right where you see it here (I’ve added the arrow to make it easier to spot) and it will often be the brightest thing around except for the actual sun.
Ice Clouds In Portland Skies Create Halo And Tangent Arc
Hundreds of miles ahead of most storm systems there are usually high, thin clouds. They’re so high in the sky and temperatures there are so cold, they’re made of ice instead of water. The clouds in this particular case are linked to an area of low pressure spinning in the Gulf of Alaska! We see its impact in the form of ice clouds over Oregon on Thursday night May 12, 2011 and on Friday the 13th.
Ice clouds are made of a bazillion (this is a slight exaggeration) individual ice crystals that each have a bunch of sides. When these line up just right with the incoming sunlight, they put on a show. In this case, they concentrated the sun’s light and created the bright Tangent Arc over parts of Portland.
And over Hood River, Oregon, Darlisa caught a better shot of the overall halo or ‘ring around the sun’ that these ice crystals created.
Sometimes, you’ll more clearly see the colors of a typical rainbow in these kind of formations–where the ice crystals act like tiny prisms to bring out a rainbow effect. You can kind of see that in the Hood River picture.
I hope you got to see this for yourself. If not–next time you do–you’ll know what you’re looking at. Hopefully that means you can enjoy the surprise in the skies even more!