jump to navigation

The dog days of winter February 20, 2013

Posted by mareserinitatis in photography, physics.
Tags: , , , ,
trackback

A lot of people ask me how I can stand the winters here.  Specifically, they just can’t imagine the cold during the winter.  I mean, there can be no up side to -10°F and 30 mph winds.  Also, those crazy Dakotans don’t seem to use MKS units.  (Psychologically, it’s far worse to think about -23°C with 50 kph winds.  Yeah, I know they’re the same, but this is why we keep using English units…)

Anyway, you’re wrong: there is an up side.  Specifically, during the months of December to February, we get to see a lot of sun dogs around here.  Sun dogs are refraction of sunlight by preferentially oriented ice crystals in the atmosphere.  (For more info, you can always check the wiki article.)  Sometimes, the refraction is really nice and they look like rainbows.  Most of the time, however, it looks like there are two ‘mini suns’ on either side of the sun.  They can be very bright.

I remember one particular instance where I had an office mate from India.  I just left the office and saw some particularly good sun dogs, so I called her up and told her to go out to the west side of the building and check it out.

“I know what those are!” she said.  “Those are rainbows! I’ve seen those before.”

“Yes, but have you ever seen them made with ice crystals?”  She was a bit more intrigued then.

Even better, but more rare, are halos.  These happen when the ice crystals are randomly oriented…such as when you have 30 mph winds.  Yesterday morning, I got to see one such halo as I got to work.  And because it was so cool, I had to share it with all of you.

Sundog over Fargo

Admittedly, it’s not the best landscape shot I’ve ever taken.  However, I was in a hurry to get inside.  It was freakin’ cold out there.

About these ads

Comments»

1. v4vikey - February 21, 2013

Nice shot.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 1,290 other followers

%d bloggers like this: