Ice Formations on White Crownbeard in My Yard, Fall 2008

 

Dr. James R. Carter, Professor Emeritus

Geography-Geology Department

Illinois State University, Normal IL 61790-4400

 

 

 

 

In summer 2008 I planted White Crownbeard Verbesina virginica and three varieties of Salvia in my yard in central Illinois, USA.  I also had Vinca growing in the yard, as in the past.  I was surprised to find ice on the Vinca.

I have seen that ice forms on cutoff stems as well as on full length stems, although the appearance of the ice may take on different forms.  So, to experience both possibilities I cut off some of the stems of the Crownbeard a few cm above the ground, and left many intact. 

Below are close up photos of two little ice formations that appeared on October 28.  Both of these ice formations are less than 5 cm in length.  The photo on the right was discussed on the master page.  It is interesting that this ice formed on green stems because weeks later after the plants died these same stems continued to support the growth of ice. 

 

 

These two formations of ice were all that appeared that day.  The formation on the right is about 1 inch or 3 cm long, and the one on the left is even smaller.  These are on small cutoff stems of White Crownbeard, Verbesina virginica.  This plant has wings on the stems, which are visible on the stem above the ice on the left.

 

This patch of tall and cutoff stems of Verbesina produced many interesting displays of ice through the fall.  The photo pair shows the two stems of White Crownbeard, Verbesina virginica, separated by 19 hours. 

 

The photo on the left was taken at 4PM as cold air was moving in and new ice was forming.  On these two stems we see ice growing out in all directions from the stem.  At 11AM the next morning the ice had become formed into a few coherent ribbons.  Obviously, those many starts of ice touch each other and become fused into thicker ribbons of ice.  As the ice continues to grow outward from the stems, it appears to us as broad ribbons.  The angle at which a ribbon grows will be determined by the differential rates of growth of the many thin ribbons fused to make the larger ribbons. 

 

On the night of November 9 I found ice growing from a number of plants throughout my yard.  It had been almost two weeks since I first found any ice, and now it was growing in many places.  I took a few photos late at night with flash.  The growths of ice were underway.  But, the next morning in better light I was able to photograph many interesting growths of ice such as this scoop of ice below.

 

These two photos show what I call a scoop of ice.  As the ice grew away from the stem it formed into two broad ribbons at about an 80 degree angle at the top of the stem.  But, lower down the stem the two ribbons emerged as one.  These photos were taken 15 minutes apart and so the shadows on the ice are different.  And, I removed the blade of grass that extends over the ice in the photo on the right.  This is on a stem of White Crownbeard, Verbesina virginica.

 

This scoop of ice was perhaps 2 inches, 5 cm, long.  I spent more time taking photos than making measurements and recording them so I am trying to estimate sizes relative to other objects in the photos.  Subsequently, close examination of these photos at the largest scales brings out things I did not see when I took the photos. The photo below is an example of this.  Here a portion of the photo above is shown at a much larger scale.

 

Here we focus on the way the ice grows away from the stem, showing how the super cooled water penetrates the stem and freezes where it emerges from the stem.  Here and in the photo above we see how three thin ribbons of ice join together into a thicker ribbon.

Immediately to the right of the stem above you can see that the ribbon of ice has broken off from the stem leaving a smooth edge of ice.  This shows that the needles of ice do not penetrate the stem for if it did that edge would not be so straight. 

 

In the photo below you can see multiple ribbons growing out the stem.  What I find most interesting in this photo is the ribbon-candy like growth in the center of the larger ice formation.  Is it likely that this single ribbon grew away from the stem only to bump into a piece of another ribbon, forcing it to fold into these overlapping ribbons as the ice continued to grow outward. 

 

This photo focuses on the center of a more complex ice formation, shown below.  In this photo we see where the ice grows away from the stem and extends out and then folds back over itself like ribbon-candy.  Note that these pages show a similar display of ribbon-candy ice extruding from a fence

 

This candy-ribbon is but the center of a very complicated ice formation at a variety of scales.  In this photo the stem from which the ice grows is obscured by the branch or blade of dry grass.  But, we see that the ice that grew out from the stem wrapped around to make a circle.  We can see that there are a number of fine strands of ice that are only linked to the main feature in one or two places.

 

A complex formation of ice around a stem of White Crownbeard, Verbesina virginica.  In the center is the ribbon-candy formation, encircled by many thin ribbons of ice.  Then on top of these ribbons of ice and the plant stems and leaves is a heavy deposit of frost. 

 

The ribbons of ice are formed by super cooled water penetrating through the stems of the plant and freezing in the colder air when they encounter an ice crystal.  The water continues to move up the stems to feed the growing ribbons of ice.

Frost by contrast comes about when water vapor in the air becomes saturated and is deposited on a surface as an ice crystal.  If the air temperatures are above freezing we get the formation of dew, but when it is below freezing the moisture is deposited out of the air as frost.  In the photo above and in the one below you can see that frost has been deposited on the ribbons of ice as well as the leaves and blades of grass.  So, I must assume that the ribbons of ice were formed or at least partially formed before the heavy deposition of frost.

 

The red Japanese Maple leaf adds to this photo of two growths of ice from White Crownbeard stems.  A thick layer of frost has been deposited on top of many of the surfaces.  I suspect the reason why frost was not deposited in the center of the red leaf and on the brown leaf is because they are closer to the warmer ground and those surfaces did not fall to the frost point temperature.   

 

The photo below is one of those lucky shots where a shaft of sunlight penetrating between the branches of a Spruce tree illuminated the ice ribbons and gave an etheral glow in the background.    

 

The photo above caught the sunlight passing between the branches of some trees while giving a back light to these ribbons of ice on a stem of White Crownbeard, Verbesina virginica.

 

There were many ice formations in this area in the month of November.  So, I kept returning to this area and captured photos of the ice in many stages of development.  Of course, you cannot get a good photo until the Sun is high enough to illuminate the area, or you will have to use flash.  In general, flash does not give very good results.

 

This is the same ice formation 25 minutes later.  The Sun adds beauty but it also causes the ice to melt.  Note the thin ribbons of ice that have fallen off.  The fact that the ice falls off in thin layers shows that it was formed as many thin layers, which sometimes grow into each other and fuse together and at other times remain apart.  Here many of the layers have remained isolated and separate.  

 

You can see some green leaves in the background of these photos showing that the ice occurs during that time that the cold air moves in and the plants are starting to die.  The formation of the ice does not seem to be related to the stage in the life cycle of the plants but rather relates to those times when the moisture in the soil is still above freezing but the air temperature near the ground surface is below freezing.  This situation prevails in the late fall in this part of the middle latitudes.  This is not likely to occur in spring because then the soil is likely to be frozen while the air temperatures are above freezing. 

 

In this same area this photo pair shows the same ribbons of ice from two sides.  There is not an obvious front or back. In this case we see that the many thin ribbons growing out from the stem become fused together into two composite ribbons.

 

The photos above show the growth of ice from a single stem but it is quite common to have ice growth from a complex of stems and merge together into a mass of ice ribbons, or what might be called ic flowers.  It does not matter if the stems are intact or cutoff.  This large mass of ice, perhaps 4 -5 inches (10 - 12 cm) tall, is a good example of the ice growing together from a complex of stems.  Some of this ice reminds me of the complex formations of ice I found in northern Kentucky in 2005.   

 

Fairly large stems of White Crownbeard provided the base for these sweeps of ice ribbons up from a gravelly surface.  The sunlight passing through these ribbons gives definition to their thin, parallel forms.

 

I like the ethereal nature of this image.  I took many photos of this ice at a high resolution and have looked at the patterns of ice at many scales of resolution.   The image above had to be greatly reduced to fit on the web page, and then it was cropped significantly.  The image below is at a much higher resolution and gives a unique perspective.

 

This is a more detailed photo of the ice formations shown above.  Here the fine nature of the thin ribbons of ice are quite evident.  Sorry to say such ice lasts for only a couple of hours, once the sunlight hits it.

 

Speaking of lasting for hours, the two sets of photos below tell us something about the birth and death of these ice formations.  This photo shows two views of the same ice formation.  Here we see the ribbon nature of the ice, which in total gives the basis to call these ice flowers.  This formation of ice was perhaps 4 inches (10 cm) tall. 

 

This photo pair shows the same ice formation from above and from the side at 9AM.  From above we see many separate ribbons radiating out from the stem. But note how many of the individual ribbons merge together with other ribbons.  On the right we see a full length of stem between ribbons of ice that curve away in opposite directions.  This is on White Crownbeard, Verbesina virginica.

 

But, this ice cannot last forever.  Below we see the last remnant of the massive display of ice, now a fallen victim of warming.  This is not from global warming but the diurnal cycle of warning and cooling during the day.  On some days the ice lasts through the day and into the next.  In some cases it may go on for days if the temperature does not rise above freezing and direct sunlight does not fall on the ice.  Below we see the juxtaposition of old and new ice. 

 

Twelve hours later at 9 PM we see new and old ice formations together.  The smooth ice on the right half of the photo is a piece of the large ribbons that partially melted during the day and fell off the stem.  On the left we see the stem where new growths of ice are forming.  This new ice starts as many sprites and looks very disorganized, which it is.  With time these sprites are likely to merge together into ribbons.

 

However, in this case, I do not know if these sprites of new ice merged together because warm air moved in over night and rain followed.  The next morning it was all gone.  But, this photo tells us much about the processes of the growth and decay of ice on plant stems. 

This is one of many pages supporting the discussion of ice formations with diurnal freeze/thaw cycles.  Return to the Diurnal master page.

Feel free to contact me at  jrcarter@ilstu.edu  if you see any ice of this nature in your early morning outings.

 

 

Return to the master page of diurnal freeze/thaw web pages of Dr. Jim Carter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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