Ice core obtained for crystallographic analysis, Manitoba (Canada), March, 2012
There are different types of river ice, and one way of assessing ice type is by analysing an ice core. A Kovacs ice corer is shown here with an ice core still in the barrel. After packing the ice core into a cooler and transporting it to a laboratory cold room, the ice core can be cut into thinner sections and observed through cross-polarized light. The image here shows a section of thermally grown columnar ice, which is evident from the relatively large ice crystals that were invisible when using the naked eye alone.
(photos by Shawn Clark, University of Manitoba: Olympus StylusTough-6020 – Photo 1 (March 14, 2012): f/10, ISO – 125, FL 5 mm, 1/60 sec. exposure time; Photo 2 (Ice Cutter – March 23, 2012): f/3.9, ISO – 125, FL 5 mm, 1/30 sec. exposure time.)