Photo Credit: bobby boyd
On the morning of December 11th, 2009 ice was observed around the stems of some of the plants here at the National Weather Service Office on Old Hickory Lake near Langford Cove. This phenomena is known as Frost Flowers or sometimes called ice flowers. When the ground is not already frozen the sap in the stem of the plants will expand, causing long, thin cracks to form along the length of the stem. Water is then drawn through the cracks via capillary action and freezes upon contact with the air. As more water is drawn through the cracks it pushes the thin ice layers further from the stem, causing a thin pedal to form. They usually are visible just after daybreak when temperatures are very cold, as was the morning of the 11th when the temperature was 18 degrees at the time I took the pictures. I have seen them last through the daylight hours but often times they will melt or sublimate when exposed to sunlight.
National Weather Service