During the last few days we have had one of the deepest cold spells in recent memory. Temperatures have been in the -20s to -30sF for almost a week and the forecast calls for it to continue for at least another week. This weather is nothing remarkable, historically. When I first moved to Fairbanks, in the 1990s, winters were mostly in the -20s, with occasional forays into the -40sF. For the past 10-15 years, the winters have become so much warmer that normal conditions from the good old days seem like a significant cold spell.
Something I used to see more commonly is frost curtains around poorly-sealed doors. Our chicken coop has such a door, by deliberate design. Because the air in the coop is so humid, the exterior door is prone to icing shut. In order to open the door, we have to kick it (if it seems loose enough) or use the heat gun to melt it open. Neither method is ideal. The simplest solution has been to widen the gap above and below the door and clean the frost away each time we enter the coop. This solution was based on the logic that, for lack of ability to prevent air leaks we have intentionally created them where they are most-conveniently dealt with.
The air gaps in the exterior doorway result in the work side of the coop being a bit colder than we would prefer, but the interior partition wall and door maintain the layer side of the coop at temperatures warm enough for the birds to avoid too much discomfort. This winter, the coldest it has gotten in that side of the coop is 35F.
At this time of year, there is little risk of the door freezing shut because the temperatures are so low that the water vapor freezes into tiny crystals that are carried out with the escaping air. Because there is currently little risk of a problem with the door, I am able, without distraction, to appreciate the beauty of the frost formation.
I think the frost curtain resembles a bird’s wing, which is fitting for its location. Seen closely, the long strands of frost look very much like feathers. As I was taking pictures for this post, it was -27 F and the screen on my phone was sluggishly responding to touch. In consequence, I ended up with a great many pictures to choose from!
Never having heard of a frost curtain, I certainly haven’t seen one in my 86 years. Marvelous to observe!! I’d find myself studying the various aspects of such a gorgeous creation of nature, I’m quite sure, despite the temperature.
Being in the lower 48, though, I think I’ll have to be satisfied appreciating delicate cobwebs whose art is simply exquisite, as well.
Thank you for the image and explanation.