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These needle shaped ice crystals were sticking up out of the ground. How did they form?

Answer:

These are ice needles. They form in soil that is water logged, usually on a slope. The ground temperature has to be just above freezing, while the air temperature is well below freezing. As the water at the surface cools to the freezing point, it expands upwards and starts to freeze. More water moves up to take its place, and expands as it freezes to the bottom of the previous ice. This process continues, building a long, needle shaped piece of ice. These were only about two inches long, but they can get up to a foot or more in length.

A similar process forms ice ribbons that grow from the stems of plants and from metal pipes. You can sometimes even see this in the ice cube trays in your freezer, with a thin spike of ice growing up in the center of an ice cube. If you want to try this, fill a very clean ice cube tray with distilled water. Put the ice tray in just before you go to bed, so nothing will bump or vibrate the freezer. No midnight snacks! If you are lucky, you may have an ice spike the next morning.

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