Wild Weather

Before anyone says anything else, yes, I do understand that I'm living in the Arctic where the tendency this time of year is for the temperature to be very cold.  I'm not complaining (much), just commenting on some weather phenomena and an extended, prolonged, seemingly never-ending cold spell.

It seems to me that on a bright, calm day, the minus teens or even down to -20 F can be quite comfortable.  Towards -30 F is chilly but bearable.  Drop to -40 F and throw in some wind, and you spend a considerable portion of your day planning out your dress and routine -- at least I do -- and you might even postpone some errands for a while.  Based on my experience during the last two winters, that strategy would work.  If it was very cold or very windy (thus making it feel much colder), you might wait a day or two, and then the weather would be nice again.  Well, for the past few weeks we've had temperatures staying steadily around -25 F to -35 F with varying wind chills, and a few days with - 40 F or less.

It did get a little colder than this screen shot, but this was the closest one I captured.  That day, at that moment, the wind was calm, but it's amazing how much of an effect wind chill has.  I have a much better understanding of it having lived up here.  (I've come a long way from when I was a kid and thought people were calling it the "windshield factor."  Hey, it makes sense...the windshield of the car on a cold day tends to feel colder than the air feels to the touch!)

When you get temperatures this cold, things do start to happen.  Materials react differently.  Clothing that once seemed to be the warmest feels like you're wearing next to nothing.  Travel becomes more dangerous.  So you start to see weather warnings like this one.  I especially like the part that says "exposed flesh will freeze in less than 10 minutes."  I wear mittens most of the time because they keep your fingers warmer, but it's hard to get your keys out of your pocket, find the right key, and open the door with them.  So, I take off my mitten, get keys with bare hand, and open the door.  It's really no big deal.  It's not like you're standing around in liquid nitrogen.  But after reading this, I sometimes laugh at myself because I hurry just a bit more to get the key in the door and get it open!

Another thing that happens at around -40 F is ice fog.  Water freezes at 32 F, right?  Well, not always.  If it doesn't have a nucleating agent -- some kind of molecule that encourages and ice crystal to form around it -- water can become supercooled.  It's still in liquid form with a temperature below its freezing point.  However, at around -40 F, even the cleanest, purest water will freeze.  Cold air can't hold as much water as warm air, and at -40 F, saturated air "squeezes out" its water vapor as liquid or ice crystals.  The fog that forms is called ice fog.  In places like Fairbanks where you get temperature inversions and there's pollution from cars (giving something for the ice to nucleate on), ice fog will form at warmer temperatures of around -20 F.  Here are a couple of pictures.  Of course, they just look like any old fog, but now you know what causes it!  The one with the sun was taken close to 2:00 which is about noon -- when the sun is highest in the sky -- for us, so you can see how low it still is.  We're gaining 7 minutes a day, though, and tomorrow we'll be up to a 4 hour day!

Ice Fog

Sun burning through ice fog at high noon