Polar Vortex Brings Stunning "Sun Dogs" To the Midwest
Language
Reading Level
Listen to Article
The blast of Arctic air, which has caused a once-in-a-generation deep freeze across the US Midwest, has paralyzed the region’s cities and towns. Hundreds of schools are closed, thousands of flights and trains have been grounded, and most businesses were forced to shut. Authorities are cautioning residents to stay indoors during this unprecedented chilly weather pattern, which is cold enough to freeze boiling water in midair and can result in frostbite in as little as 5 minutes. The polar vortex’s only silver lining? The beautiful sun dogs being observed at many of the affected areas.
Also known as mock suns, or parhelia ("with the sun”), the natural optical phenomenon is one of several kinds of halos caused by the refraction of sunlight by the ice crystals in the atmosphere. Sun dogs typically appear as a pair of subtly-colored patches of light at an angle of about 22 degrees on either side of the Sun. Their hue ranges from red (closest to the Sun) to blue (towards the outer edge). According to experts at the National Weather Service (NWS), sun dogs are most visible when the sun is closest to the horizon – just after sunrise or just prior to sunset – since the atmosphere is thicker close to the ground.
Global News weather specialist Mike Koncan explains the phenomenon further, saying, “Ice crystals form hexagonal prisms and refract the light, creating this effect. The key is the prisms remaining still as they fall. Only crystals with their prism axis roughly perpendicular to the sun’s rays will allow light to pass through two sides.”
In some areas, the extreme weather has also resulted in another atmospheric phenomenon. Known as "22° halo," or simply “halo,” it appears as a large ring with a radius of about 22° around the Sun or Moon and is the best known of all the halos caused by ice crystals. The type of optical illusion that appears depends on whether the ice crystals are horizontally-oriented (sun dogs) or semi-randomly scattered (halo) in the atmosphere. Both are stunning!
Given that the extreme temperatures are expected to linger for a few more days, there will be no shortage of sun dogs and/or halos to lift the spirits of the residents enduring the cold spell. For those of us unable to see them in person, numerous spectacular images are being shared on social media.
Resources: NWSSiouxFalls, Weather.gov, Wikipedia.org
Get the Workbook for this article!
Workbook contains: Article, Reading Comprehension, Critical Thinking Questions, Vocabulary in Context (+ answers), Multiple Choice Quiz (+ answers), Parts of Speech Quiz (+ answers), Vocabulary Game (+ answers)Cite Article
Learn Keywords in this Article
412 Comments
- ITSAMEME#21over 5 yearsI think it's amazing because it's so pretty.
- memeover 5 yearscool
- Little dogover 5 yearsCool
- junior over 5 yearsi think it looks awesome i wish i can see it in person and every guys had good response i hope you see it in person to.
- Emerie over 5 yearsi love the artical because it has a lot of things i did not know about.
tuzubobemadiciover 5 yearsi thought the whole thing was called a sun dog but no its a halo lol- Brownie_Girl726almost 6 yearsThis is sooooo cool I wish I could see it in person!!!
- jeffalmost 6 yearscool artical and my name is jeff
- jeffalmost 6 yearscool
- Personalmost 6 yearsIt looks so pretty on pics. and in pearson.
