Snowflake Field Guide Part 1 - Snowflake Classification
When your Spatial & Stellar Dendrites are piling up on the garden and it's too cold for your Sectored Plates to melt, and Rimed Crystals are predicted, it's time to learn more about them.
The 1951 International Snowflake Classification System
This system defines seven principal snow crystal types as plates, stellar crystals, columns, needles, spatial dendrites, capped columns, and irregular forms. To these are added: graupel, ice pellets and hail.
Stellar dendrites have six symmetrical main branches and many randomly placed sidebranches.
Like the stellar dendrites, sectored plates are flat, thin slivers of ice that fall to earth in a stunning diversity of complex shapes.
Columnar crystals are the main constituents of many snowfalls. These hollow columns are hexagonal, like a pencil, with conical hollow features in their ends.
Columnar crystals can grow so long and thin that they look like needles.
Spatial dendrites are made from many individual ice crystals jumbled together. Each branch is like one arm of a stellar crystal, but branches are oriented randomly.
These crystals started out growing as columns, but switched to plate-like growth. This happens when a crystal is blown into a region with a different temperature.
Snowflakes can have a hard life blowing about in a turbulent cloud, so that many arrive on the ground broken, ill-formed, and generally in bad shape.
Snowflakes are made of small water droplets. Droplets that freeze onto a falling snow crystal are called rime. Sometimes a snowflake becomes just a ball of rime, called graupel, or soft hail.
Wilson Bentley was the first person to successfully photograph snowflakes.
The Bentley Snow Crystal Collection of the Buffalo Museum of Science is a digital collection of stunning, un-retouched images of Wilson A. Bentley’s original glass slide photographs. Wilson Bentley was the first to discover that no two snowflakes are alike.
When it looks like this out your office window (photo at top), thoughts turn to dendrite build-up. Years ago, as a direct mail promotion, I created a Snowflake Field Guide for the Buffalo Museum of Science. Each day this week, I'll post some facts about flakes. It was originally intended for kids, but I didn't know much of this info when I started.