Blue Sky Scavenger Hunt

Most people don't think twice about blue skies... 

Sunny. Mild. Boring. Uneventful.

In honour of the controversial 'Special Weather Statement' issued by environment Canada, calling for slightly warmer than normal temperatures this weekend it's time to have a bit of fun... 

I'll walk you through several atmospheric phenomena that can be found on bright, sunny days. 

1. Blue Field Entopic Phenomenon

Look up at the sky next time it's clear and sunny. You'll see something that you've probably never noticed before. It's that subtle.

Focus on the brightest blue sky you can find, and suddenly you should see many white specks flying around near the center of your field of vision! These are called 'blue-sky sprites' and it's been coined the blue field entopic phenomenon.

Believe it or not, you're seeing your own white blood cells moving though your retina.

Blue light is absorbed by the red blood cells and your brain edits this out and fills it in, but white cells are much more rare. They fail to absorb the blue light, creating gaps in the blood columns.  

If you want to read more about this effect, check out the Wikipedia page.  

  GIF Author:   Unmismoobjetivo   (Wikimedia Commons)

GIF Author: Unmismoobjetivo (Wikimedia Commons)

2. The Sun Dog



The sun dog is one of the most common atmospheric optic processes related to the common ice halo. When the sun is low on the horizon, look up at approximately 22 degrees, and you'll find two bright bands at the same height (shown above). Colours vary with red being more common closer to the sun, as shown in the picture above. 

3. The Mirage

I won't go into great detail, as there's already a fantastic explanation of UW professor Cliff Mass

But the basics:

  • Warm air travels over the cool ocean waters of the Georgia Strait, which distorts the horizon, creating a superior mirage
  • This creates a lens that effectively bends light and distorts the horizon, so head down to the shore and try to see this cool mirage in action 

Below is an excellent example shot by Greg Johnson. Prepare to be amazed...

4. Crepuscular Rays (Sunrays)

  • This evening will be perfect to witness some stunning sunrays, as broken cloud cover is needed to see this event effectively. 
  • The suns rays are effectively scattered with pollution and other atmospheric aerosols (dust, pollen etc.)
    • These parallel columns of sunshine are truly stunning and surreal (see example photo below)
 Photo by Kelly Larsen

Photo by Kelly Larsen

5. Circumzenithal arc

  • The first time you see this halo, you'll be sure to never forget it. Often called a grin in the sky, or an upside down rainbow.
  • the 22° circular halo and sun dogs are also featured in the photo example below, along with other, less common atmospheric optic effects, which I may discuss in future blogs
 Photo credit:

Photo credit:

Please practice safe sun behaviours and always wear sunglasses and avoid looking directly at the sun for any prolonged period of time. 

Happy Hunting.