The Rime Is Sublime - Nature's Artwork Revealed

 

 

A look across the Roan Massif from Round Bald, looking out to Little and Big Hump mountains reveals the beauty of the snow and rime ice adorning the landscape. 

Wintertime is a magical season in the mountains.  In addition to a lot of snowfall, there are all sorts of other atmospheric processes that maximize their effects when you deal with elevation. One of my favorites is rime ice.

Rime ice forms when super-cooled water droplets freeze upon contact with surfaces below 32 degrees. It may sound like science fiction, but tiny water droplets, like you see in fog near the ground or up in the clouds, will actually remain in their liquid state when the temperature is several degrees below the freezing mark.  Also known as freezing fog, these droplets float along on their merry way in that sub-freezing air until they contact an object, whereupon they immediately freeze to it. 

If it’s a roadway that has not been treated with salt, especially a bridge or elevated highway, freezing fog can create very dangerous, icy conditions.  On an aircraft  that flies through a cloud of super-cooled water droplets, rime ice can quickly build up on the wings and potentially weigh down and change its aerodynamics.  In fact, rime icing on aircraft has been responsible for some catastrophic accidents. However, if you are on a walk where rime ice has occurred, whether it’s on a twig or tree or building, you may get to see some amazing sculptures. On a recent hike, I was treated to just that.

In calm or weak wind conditions, the process of riming will produce icy spikes as drops accumulate on objects.  In stronger wind conditions, the droplets impact the windward (direction from which the wind is coming) side of the objects and continue to build into awesome billowy, aerodynamic shapes and designs as shown below.  The "whitish" appearance to the formation is due to tiny air pockets in between the frozen droplets that help to scatter light waves so it appears white. I encourage you to click on the images below to get a look at the details, it's amazing! 

 

These two images above are in different locations/perspectives on Round Bald atop The Roan Massif. They are proxies for wind direction, the photo on the left has winds coming from the left side of the image and the one on the right has winds coming from the right. 

The photos above were from a trip I made up to Roan Mountain, on the North Carolina-Tennessee border, a perfect place to see these formations. The Roan Massif is one of the most beautiful and spectacular sections of the Appalachian Trail. The Trail itself climbs through the clouds to over 6,000 feet and passes through the largest stand of Catawba rhododendrons in the world. 

When I trekked up to the “The Balds” at Carvers Gap, a region of treeless meadows that extend along the ridges at 5,500-6,000 ft., that morning, I was treated to beautiful works of Nature!  Because of the lack of dense forests across The Balds, widely spaced trees, dormant fields and even rocks and boulders are open to the prevailing wind. When super-cooled clouds race across the ridges, they paint the vegetation and topography in a beautiful icing of white. 

This lone pine tree atop Round Bald looked like a nice photo opportunity on this beautiful, sunny day.  As we got up close and looked at the tremendous build-up of rime ice on a pine branch, we were in awe!

The park road up to the rhododendron gardens at Carvers Gap is closed in the winter to traffic, but its a perfect place to hike and see some of the more heavily vegetated area adorned with rime ice. In contrast to the open areas, where the evidence of "wind riming" is readily apparent, in sheltered areas the riming is more uniform.

 

Even after a few days, a walk up the park road unveiled some beautiful formations of rime ice, still stuck to the sheltered trees. 

Every season brings a new palette for Mother Nature to work her miracles. Winter can be especially fascinating, in some cases "other-worldly". From beautifully crafted snow crystals, to the rime ice we have gotten to know in this blog, winter is a great time to see what is out there. With a little effort, you too can uncover these beautiful aspects of the world we live in!

   

 

Mother Nature’s Snow Crystal Workshop

Snowflakes have to be one of the most interesting gifts of nature.  Whether you watch them fall from the sky from inside your home or get out to enjoy all of the activites that fresh snowfall has to offer, snow is one of those "other-wordly" parts of our daily lives for those who live in "snow country".  When you take the time to look closely, I mean really close to a snowflake, or more accurartely a snow crystal, what you will uncover is a whole new world of wonder.  I want to share some of the photographs I have taken of snow crystals over the past few years because they are just so beautiful.

Snowflakes have been around of course long before the dawn of man. I can imagine our early ancestors getting a close look at those flakes and wondering how in the world they were formed.   According to Kenneth Libbrecht's Snow Crystal Web Site  snowflakes first appeared in recorded history when individual snow crystals were identified and described as having that unique 6-sided symmetry.  Way back in 135 B.C., the Chinese scholar Han Yin wrote “Flowers of plants and trees are generally five-pointed, but those of snow, which are called ying, are always six-pointed.” Much later, in the 17th century, Renee Decartes gave detailed, naked-eye accounts of snow crystals but it was Johannes Kepler who provided the first scientific theories on snow crystal formation. 

Johannes Kepler gave this gift, The Six-Cornered Snowflake, to the Holy Roman Emperor Rudolf II for New Years' back in 1611.  

As you will see below, in the 1930s Uchikiro Nakaya, a brilliant researcher, developed a classification method for snow cyrstals based on the temperature and humidity profile in the atmosphere. By the way, my snow crystal "hero" is Wilson Bentley, who lived in Jericho Vermont in the 19th century and as an amateur scientist compilied one of the most thorough snow crystal photo catalogues out there. I will write about him and my experience working with his original photo plates and logbooks in a later blog entry, but I digress.  

Stellar dendrite snow crystal, photographed on a piece of black fleece with an Olympus TG-6 camera. This is a great camera for macro-photography, with "stacking" software built in.  Focus stacking is a digital image processing technique which combines multiple images taken at different focus distances to give a resulting image with a greater depth of field than any of the individual source images.

That stellar dendrite crystal above is one of my favorite specimens I photographed in the Tennessee Appalachians in February, 2020.  The term snow “crystal” is a more accurate way to describe individual snowflakes. The snow crystals may not be any larger than 2 to 3 millimeters in size.  In fact, those big fluffy snow flakes that you may be familiar with are often made up of hundreds of individual branched snow crystals that lock together to make flakes like this quarter-sized beheamoth that crashed onto my deck one winter day.

 

Take a close look at the snow crystals below and see how they are that specific geometric shape, 6-sided, or hexagonal.  That's not a coincidence.  All snow crystals are based on the hexagonal shape. This isn’t magic either, although I would say that the way in which nature makes these beautiful, natural sculptures is in some ways so much better than plain old magic. 

Hexagonal plate (left) and embryo (right) photographed under a microscope, backlit by a LED flashlights with color filters (pieces of plastic page protectors) attached. Notice the 6-sided theme in every single crystal. 

How Do They Form

It all starts with water, a really neat substance of nature.  As you know, water is a molecule made up of 2 hydrogen and 1 oxygen atoms (H₂O).  In its solid state, these water molecules lock together into the 6-sided shape we all know and love as shown in this beautiful animation below.  In this blog I am not going to get into all of the physics and chemistry associated with the complete processes that produce a snow crystal, but I will touch on some of the basic concepts.  

(courtesy Kenneth Liebreccht, snowcrystals.com)

You may all be familiar with the traditional snow crystal, that 6-armed Christmas ornament or piece of jewelry like the image below.  In reality however there are many, many different types of snow crystals and it wasn't until I started photographing them that I really began to unlock the true miracle of this atmospheric factory that produces so many varieties. There are dendrites, plates, columns, capped-columns, prisms, needles, and other even more exotic designs.  

Traditional 6-sided spatial dendrite that most people are familiar with when you mention the term snowflake. Note the amazing hexagonal symmetry that is maintained in so many designs as you move out from the center, or nucleus, of the crystal.

Snow crystals begin with a simple hexagonal prism having two basal facets, or sides, and six prism facets.  Depending on a host of conditions withint the cloud, the crystal will either grow from the basil facet or the prism facet. If the ice nuclei grow outward in the hexagonal prism, you end up with a flat plate or dendrite crystal. Evetually, legs of  the crystal then grow outward from one of the six points in the hexagonal plate, which “stick out” into the moist air just a bit more than the sides. If the crystal grows upward from the prism face, you get a hexagonal column as the crystal grows in a vertical manner as shown below.

Ukichiro Nakaya was one of the first scientists to develop a system for snow crystal formation. As a result of his research work back in the 1930s, he developed the Nakaya Diagram, which described the relationships between the humidity and temperature in the clouds and the type of snow crystal that forms. Although the physics behind snow crystal formation is exceptionally complicated, the basic ideas are shown in his chart below.  What is so fascinating about the snow crystal is that its shape and design are a direct result of the atmospheric temperature and humidity profile it falls through on its way to earth. Nakaya so eloquently described the snow crystal as "A Letter From The Sky" because you could "read" the meteorological information "written" on the snow crystal.  

Observing These Sculptures of Nature

Living in Buffalo, NY I didn't have to look far for snow.  Even as a kid catching snow crystals on my tongue, they intrigued me.  I really discovered their intricate beauty with the help of my Black Labrador Retriever, Smoky.  I remember looking at snow crystals falling onto his fur one snowy day. His fur was fully insulated from his body warmth so the snow crystals did not melt.  That black fur served as the perfect background to look closely at the snow crystals and what I saw opened a whole new world for me. 

Snow crystals on a fleece jacket. This photo was taken with a plain old iPhone 5, in a future bolg I will show you how to get started photographing your own snow crystals.

Through my research work, I eventually obtained an old microscope, and with my little Canon G6 Point&Shoot camera and a couple dollars of plumbing parts to attach the camera to the eyepiece on the scope, I began to see what so many other scientists have discovered. With lots of experimentation I started finding success in documenting these amazing shapes.  In anticipation of a snow event, I couldn't contain my excitement when I started capturing the specimens and putting the glass slides under the microscope. More recently, with the improvement in macro-photography cameras like the Olympus TG-6, I was able to capture my photographs without the use of the microscope. In this section of my snow crystal blog, I will share some of those images below. Just click on each one to get an enlarged view and take the time to look at the details, its hard to believe they come naturally form the sky!

 

These crystal photographs are taken with the old microscope and Canon G-6 camera. They are post-processed to put them on nice backgrounds.  The details that you can see in each crystal are truly amazing!

Spatial dendrite photos taken directly with my Olympus TG-6 camera. With this camera, you can get a much better look at the crystals in 3-D.  The crystal on the left is attached to the hairs of an artist's paint brush. The threads in the background of the other images are the black fleece that I use to collect my specimens. 

  

These snow crystals all have a few things in common. Each one of them is covered with all of those little frozen droplets. In one of my next blog entries I talk about how this process works. Stay tuned... 

I plan to author a few more blog entries on snow crystals soon. They will include all of my instructions on how to get started photographing snow crystals, a nod to my snow crystal hero, Wilson Bentley, whom I consider the "Father of Snow Crystal Photography", and finally and extensive gallery of some of the hundreds of snow crystals I have photographed, and there are a few that are really "other-worldly.  Stay tuned for that and much more!!