Wednesday, July 28, 2010

watery wednesday: ice needles




http://waterywednesday.blogspot.com/
My cousin Alicia visited me. She had been in the mountains skiing at Mt Ruepehu. She took this photos. Looking from the thumbnail, I thought they were icicles. But when I looked at the big picture, I thought they looked like ice needlea and when I went to ggogle search, I wasn't wrong. They were called ice needles.

I have not seen ice needles before in Canada or in New Zealand http://annkschin.blogspot.com/2008/11/winter-in-mt-ruepahu.html. Neither have I seen them on the blogs. Is this phenomenon quite rare? It has a characteristic filamentous appearance with individual needles extending independently and in fascicular bundles.

Thank you Alicia for this eye opener.

Addition:
Jama asked if it is dangerous, it makes me think of the Indian Gurus who lie down on a bed of needles.

My Cousin and her friends were very curious about the needles. Initially they thought there were grass or twigs, upon examination, they were shards of ice needles.

Needle ice is a phenomenon that occurs when the temperature of the soil is above 0 °C (32 °F) and the surface temperature of the air is below 0 °C (32 °F). The subterranean moisture is brought to the surface via capillary action.

The ice needles are typically a few centimetres long. While growing, they may lift or push away small soil particles.
http://en.wikipedia.org/wiki/Needle_ice

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