Interesting Ice Formations in my yard, Fall 2008

Dr. James R. Carter, Professor Emeritus

Geography-Geology Department

Illinois State University, Normal, IL 61790

This is one of a collection of web pages showing what are sometimes called Ice Flowers, Frost Flowers and Ice Ribbons growing on vertical plant stems.  Since first accidentally finding such ice in 2003 I have been on a search to find the right plants on the right days to see such ice.  I learned about a few of the plants are likely to support the growth of ice and tried to see if I could grow those plants.

In summer 2007 I planted seeds of White Crownbeard, Verbesina virginica, in my yard in central Illinois and I found success.  I also found ice on a stem of Salvia in my yard last year.  So, in summer 2008 I planted White Crownbeard and a similar yellow flower and three varieties of Salvia.

This is one of three pages showing ice in my yard this fall.  Another shows ice formations in two places (in and near buckets and beside trees and tall shrubs)  on White Crownbeard stems.

The other shows ice formations that grew on stems of Salvia and Vinca.  These are nice flowering plants that exist in many gardens.  Check this out, then look at your garden next fall and see if you have such ice.

It proved to be an interesting fall.  I had ice on the stems of White Crownbeard and no ice on the yellow variant.  All three varieties of Salvia produced ice formations, but one much later than the other two.  And, I had ice on Vinca, a common flower planted for the beauty of the flower but surprisingly I found ice on its stems in November.

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 a few inches above the ground and left many intact.  The photo below shows my patch of stems growing in the middle of the yard, away from trees and the house.  Both types of Verbesina are growing here but ice formed only on Verbesina virginica - White Crownbeard. 

This photo shows both tall plants of Verbesina with green leaves and to the front one can see a few cutoff stems.  The tallest plant is about 3 feet, or 1 meter, tall. In late October I awoke to cold NW winds with temperatures below freezing.  It had been quite warm, and we had more than an inch of rain a few days before and the soil was still moist.  I checked my plants and saw two little bits of white on two little stems.  Those two ice formations are in the lower, left corner of this photo.  The fact that the only ice this day was on these two stems tells much about the process of ice formation.  I found no frost on the ground, but my shoes got wet from walking on the grass.  But a car nearby had frost on the windshield and there were these two formations of ice.  I put thermometers out, one on the ground under a cardboard box and the other no top of the box.  The one on the ground read 34 and the one exposed to the sky read 28 (in degrees F). Thus, the warm ground kept ice from forming there, the big leaves on the stems kept the lower stems from cooling by radiating to the clear sky.  But these two little cutoff stems had just the right conditions to permit ice to form on the stems.

Below are close-up photos of those two little ice formations.  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 same 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 comes out and freezes along thin cracks in 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. 

A couple of weeks later I found this interesting formation of ice in this same area.  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 possible that this single ribbon grew away from the stem only to bump into a piece of fellow ribbon, forcing it to fold into these overlapping ribbons? 

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.   

This collection of photos was taken in a small patch of stems of White Crownbeard and a similar plant with yellow petals.  However, I never found any ice on the known stems of the yellow-flowering plant so I must assume all of this ice was on the White Crownbeard. 

I found much more ice this fall, but those photos will appear on other pages.  Stay tuned, more is coming.

Thank goodness for the Internet and digital cameras for they let us exchange information about these attractive ice formations.  With time I hope to expand the web site to portray other views from this interesting month of ice.  Feel free to contact me at [email protected]  if you see any ice of this nature in your early morning outings. See http://www.jrcarter.net/ice/ for my master page on ice flowers / ice ribbons

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