January 5, 2011

Ice Needles by Naturalist Eric D'Aleo

It’s amazing what a difference a cold, clear night can make at this time of year. Recently the morning the temperature reached a low of 14 degree Fahrenheit at 6:00 a.m. No cold temperatures set by any means, but the result was spectacular! I was leading the Blue Heron preschoolers on an “exploration” that morning when one of the young girls noticed that the ground seemed to be moving “funny” and sounded “crunchy”. After stopping and looking, sure enough, needle ice had formed about an inch below the duff. As the temperature dropped below freezing during the night, the moisture in the ground that was above freezing was brought to the surface by capillary action. Once at the top, the water froze and expanded, pushing the ground upward where we found it the following morning. After a few minutes of exploration and observation the children were ready to move on. I however, decided to continue to learn more about these and other unusual ice formations. If you would like to learn more, take a look at the link below about ice formation and their daily freeze and thaw cycles at this website by Dr. James R. Carter, Professor Emeritus Geography-Geology Department, Illinois State University: http://my.ilstu.edu/~jrcarter/ice/diurnal/

Photo courtesy of Eric D'Aleo

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