Beautiful Dendrites!

Mother Nature keeps some serious beauty up her sleeves. Unfortunately, sometimes you have to endure a very cold winter in the upper Midwest to get to see it with your own eyes. This is one of my favorite parts of meteorology -- the fascinating things water can do!

I was inspired to share these pictures because of an awesome recent GeekMom post about the science of snow, which includes tips on photographing snowflakes.

A billion years ago, in one of my classes, I was taught the temperature ranges at which snowflakes will form their different potential shapes. I remember getting tested on the information, too.

"At what temperature ranges will capped columns form?"

Heck if I know now, but I can find out with the click of a button....this is from Wikipedia's entry on snow:

"The shape of the snowflake is determined broadly by the temperature and humidity at which it is formed.[12] The most common snow particles are visibly irregular. Planar crystals (thin and flat) grow in air between 0 °C (32 °F) and −3 °C (27 °F). Between −3 °C (27 °F) and −8 °C (18 °F), the crystals will form needles or hollow columns or prisms (long thin pencil-like shapes). From −8 °C (18 °F) to −22 °C (−8 °F) the shape reverts back to plate-like, often with branched or dendritic features. At temperatures below −22 °C (−8 °F), the crystal development becomes column-like, although many more complex growth patterns also form such as side-planes, bullet-rosettes and also planar types depending on the conditions and ice nuclei.[15][16][17] If a crystal has started forming in a column growth regime, at around −5 °C (23 °F), and then falls into the warmer plate-like regime, then plate or dendritic crystals sprout at the end of the column, producing so called "capped columns."[12]"

I found the description from CalTech of the specific kind of dendrite I photographed, called a fernlike stellar dendrite:

"Sometimes the branches of stellar crystals have so many sidebranches they look a bit like ferns, so we call them fernlike stellar dendrites. These are the largest snow crystals, often falling to earth with diameters of 5 mm or more. In spite of their large size, these are single crystals of ice -- the water molecules are lined up from one end to the other. Some snowfalls contain almost nothing but stellar dendrites and fernlike stellar dendrites. It can make quite a sight when they collect in vast numbers, covering everything in sight. The best powder snow, where you sink to your knees while skiing, is made of stellar dendrites. These crystals can be extremely thin and light, so they make a low density snowpack."

This morphology diagram seems to sum it up pretty well:

Here are some fernlike stellar dendrite pictures I took in Bellevue, Nebraska in January 2010 when the temperature was around 0F, and they are the prettiest dendrites I've seen with my own eyes (rather than in a book). I used the digital macro setting on my camera, a Canon PowerShot SD1200IS. I wish I had the fortitude to take more pictures, but it was so incredibly cold, my hands couldn't manipulate the camera for very long. Isn't science beautiful?