Home » Science & Nature » Meteorology » Snowflakes - Page 3

Snowflakes - Page 3

© Keith C. Heidorn

sharper the ice crystal tips. At warmer temperatures, the ice crystals grow more slowly and smoothly resulting in less-intricate shapes, i.e., more needles and plates. Thus, dendrite crystals generally form in high clouds, needle or flat six-sided crystals often originate in middle height clouds, and a wide variety of shapes grow in low clouds.

For example, thin, hexagonal plate-like snow crystals form in air at 0 to -3.8^o C (32^o to 25 ^o F). In colder air (-3.8^o to -6.1^o C / 25^o to 21^o F), needle shapes occur. Long, hollow hexagonal columns appear from -6.1^o to -10^o C (21^o to 14^o F). Flower-like plates form at temperatures from -10^o to -12.2^o C (14^o to 10^o F). Six-pointed stars, called dendrites, appear from -12.2^o to -16.1^o C (10^o to 3^o F).

Wilson Bentley, The Snowflake Man of Jericho, Vermont

We owe much of our initial impressions of snow flakes/crystals to the work of a self educated farmer from Jericho, Vermont. Wilson A. Bentley combined a microscope with a bellows camera to became the first person to photograph a single snow crystal in 1885. (He describes his technique here.) Throughout the following winters, until his death in 1931, Bentley would capture more than 5000 snowflakes on film, a selection of those images are presented here.

Bentley became a local, and then national, legend and is still today known as "Snowflake" Bentley and "The Snowflake Man." His 1931 book Snow Crystals contains more than 2400 snow crystal images from his vast collection. It is likely that the belief that no two snowflakes are alike stems from this passage from a 1925 report by Bentley: "Every crystal was a masterpiece of design and no one design was ever repeated. When a snowflake melted, that design was forever lost."

More on Bentley, his life and work can be found at the Wilson A. Bentley website. [A full biography has been written by my friend Duncan Blanchard (see below), but here is a condensation of Bentley's life by Blanchard.]

For me, December snow storms often appear to have a magical quality not seen in later months. The year's first good snowfall appears to drift from clouds pregnant with large, fluffy flakes that cover the surrounding fields and meadows like a goose-down duvet. When temperatures hang around the freezing point, ironically, you can almost feel a warmth while surrounded by the falling flakes as winter is ushered in, transforming the dull brown landscape into an ermine fairyland, delicate and transient.

Copyright 2002, Keith C. Heidorn, All Rights Reserved. (Snow photographs by Wilson A. Bentley, public domain.)

The copyright of the article Snowflakes - Page 3 in Meteorology is owned by . Permission to republish Snowflakes - Page 3 in print or online must be granted by the author in writing.