Ice Needle Pattern Near Heat Source

Good day,I came across a physics phenomenon when I was recently working on an oil rig north of British Columbia, Canada: the ice needles around flare stack and incinerator.I thought that requesting help from an academic may lead me to understand the reason behind it.The snow turned to ice needles to a certain radius all around the flare stack and to a less extent around the incinerator. All the ice needles were pointing to the source of heat either the flare or the incinerator. The ice needles developed in a wonderful uniform pattern. Obviously, the farther the ice needles were from the source of heat, the shorter they were. Besides, the angle at which they facing the source of heat changed with their location. I have attached a sketch of the this phenomenon to this email message for your kind review.I would be grateful if you would answer my following question:Why does not the snow melt evenly if the heat radiates identically on the snow surface?Thank you in advance for your valuable time.Best regards,Ehsan Jalali1-403-890-9593Devon, ABCanada
- Ehsan Jalali (age 38)
Devon, Alberta, Canada

This is a wonderful question. Unfortunately your sketch didn't get through, but we'll try to answer anyway as best we can.

I can think of one reason why those ice needles would point at the source of radiant heat. That seems like it would be the most stable direction. Think of two needles, one pointed at the heat source and one pointed at an angle to that. Which will receive more thermal radiation? Obviously the one at an angle will have more surface facing the heat source, so it will absorb more thermal radiation. It will be more likely to melt. So under conditions where the temperature cycles over the day and some needles melt more and others grow more, the ones pointed right at the heat source should win.

It would be fun to test this idea by using mirrors to change the direction of the thermal radiation. You could also put a board under some of the snow, let needles form, then turn the board a little to see whether those needls melt an new ones form or whether they somehow gradually reorient, how long it takes, etc.

As for how the snow melts, I bet it does melt evenly. It's the recrystallization that breaks up into the uneven needle pattern.

Mike W.

(published on 05/24/2016)