Patterned ice cracks on trees

Description: As I took a walk a couple of days after freezing rain left ice slicks on trees in my neighborhood, I found that the ice coating certain smooth trees with very smooth bark had interesting regular patterns of lines. The lines were regularly spaced along each branch (see 10cm long pocket knife for scale). The branches were closer to vertical than horizontal, a few inches thick, and covered in ice on only the north facing side. I could not feel a bump or crack where the lines were: it seemed quite smooth, but the lines splayed out as they neared the edges of the ice (close up on left).

My best guesses are either that as the water froze, the expansion of the ice relative to the tree made compression fractures (which might explain the fact that they were too tight to feel), or that as the day warmed up the tree expanded faster than the ice, putting the ice under tension, thereby cracking it (which better explains the splaying pattern at the edges of the ice since the ice on the south sides must have melted before the cracks formed).

Page creator's name: Mickey von Dassow
Page creator's contact info: Contact through the IGoR contact page.

cracks ice pattern-formation physics trees winter

Created: 12 Mar 2014 17:49
Updated: 12 Mar 2014 18:03

Comments: 19 Dec 2014 23:06

#Comments: 4


Add a New Comment

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-NonCommercial 3.0 License