Frost flowers
Encyclopedia
Frost flowers is the name commonly given to a condition in which thin layers of ice
are extruded from long-stemmed plant
s in autumn or early winter. The thin layers of ice are often formed into exquisite patterns that curl into "petals" that resemble flowers.
weather condition occurring when the ground is not already frozen. The sap
in the stem of the plants will expand (water expands when frozen), causing long, thin cracks to form along the length of the stem. Water is then drawn through these 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 "petal" to form. In the case of woody plants and (living or dead) tree branches the freezing water is squeezed through the pores of the plant forming long thin strings of ice that look uncannily like hair i.e. "frost beard".
The petals of frost flowers are very delicate and will break when touched. They usually melt or sublimate
when exposed to sunlight and are usually visible in the early morning or in shaded areas.
Examples of plants that often form frost flowers are white crownbeard
(Verbesina virginica), commonly called frostweed, yellow ironweed (Verbesina alternifolia), and Helianthemum canadense. They have also been observed growing from fallen branches of conifers and contain enough hydraulic power to strip the bark off.
A related phenomenon
is needle ice
that is extruded from soil.
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...
are extruded from long-stemmed plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s in autumn or early winter. The thin layers of ice are often formed into exquisite patterns that curl into "petals" that resemble flowers.
Formation
The formation of frost flowers, also known as "ice flowers," is dependent on a freezingFreezing
Freezing or solidification is a phase change in which a liquid turns into a solid when its temperature is lowered below its freezing point. The reverse process is melting....
weather condition occurring when the ground is not already frozen. The sap
Plant sap
Sap is a fluid transported in xylem cells or phloem sieve tube elements of a plant. It transports water and nutrients throughout the plant....
in the stem of the plants will expand (water expands when frozen), causing long, thin cracks to form along the length of the stem. Water is then drawn through these cracks via capillary action
Capillary action
Capillary action, or capilarity, is the ability of a liquid to flow against gravity where liquid spontanously rise in a narrow space such as between the hair of a paint-brush, in a thin tube, or in porous material such as paper or in some non-porous material such as liquified carbon fiber, or in a...
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 "petal" to form. In the case of woody plants and (living or dead) tree branches the freezing water is squeezed through the pores of the plant forming long thin strings of ice that look uncannily like hair i.e. "frost beard".
The petals of frost flowers are very delicate and will break when touched. They usually melt or sublimate
Sublimation (physics)
Sublimation is the process of transition of a substance from the solid phase to the gas phase without passing through an intermediate liquid phase...
when exposed to sunlight and are usually visible in the early morning or in shaded areas.
Examples of plants that often form frost flowers are white crownbeard
Crownbeard
Crownbeard is the common name of Verbesina, a genus of flowering plants, in the daisy family . They bear yellow flowers similar to small sunflowers. The name Verbesina refers to the similarity of the foliage to that of the verbena.Verbesina species are used as food plants by the larvae of some...
(Verbesina virginica), commonly called frostweed, yellow ironweed (Verbesina alternifolia), and Helianthemum canadense. They have also been observed growing from fallen branches of conifers and contain enough hydraulic power to strip the bark off.
Names
Frost flower formations are also referred to as "ice flowers", "ice blossoms", "frost castles", "frost beard", "ice castles", "ice ribbons" or "crystallofolia".A related phenomenon
Phenomenon
A phenomenon , plural phenomena, is any observable occurrence. Phenomena are often, but not always, understood as 'appearances' or 'experiences'...
is needle ice
Needle ice
Needle ice is a phenomenon that occurs when the temperature of the soil is above and the surface temperature of the air is below . The subterranean liquid water is brought to the surface via capillary action, where it freezes and contributes to a growing needle-like ice column.The ice needles are...
that is extruded from soil.
External links
- Ice Ribbons in East Tennessee
- Extruding Ice from Steel Fences and Pipes with Diurnal Freeze/Thaw
- Frost Flowers
- Frost Flowers Photo Story
- Blossoms of Ice--from Natural History, February, 2004
- Guide to Frost
- http://www.flickr.com/photos/la_linea/ - Frost flowers (54 pictures) in Bambesch, Luxembourg, Jan.02.2010
- Crystallofolia (‘Frost Flowers’), with Stems of Frostweed (Verbesina virginica) & Marsh Fleabane (Pluchea odorata)