Needle Ice Crystals
March 10, 2006
Provided by: Andrew Heiz
Summary authors & editors: Andrew Heiz; Jim Foster; Ray Murphy
The photo above showing fascinating needle ice crystals was taken from Minnewaska Park, near Gardner, New York, on January 22, 2006. These columnar crystals formed on a dirt path after a night with below freezing temperatures. Needle ice crystals typically form during the night when seeping groundwater freezes as it comes in contact with the below-freezing air. The hydrostatic pressure of the groundwater below the surface forces the newly-frozen "cap" above the surface. In non-freezing conditions, the forced-out water would just run off. For these columns to be created, the soil temperature must be above freezing. Note the pine needles on the right of the image for scale.
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