Metamorphism:
From the instant snow hits the ground, it begins an endless
process of metamorphism. No commonly-occurring substance in
nature undergoes such dramatic and rapid changes because snow
exists near its “triple point”, meaning that solid,
liquid and vapor phases all exist at the same time. In other
words, small, subtle changes in temperature, pressure, humidity
and temperature gradient can have a dramatic effect on the type
of snow crystal that forms. This makes snow one of the most
complex and changeable substances on Earth. Here is a condensed
list of the most common types:
|
| Type |
Also called: |
Looks like: |
Where you find it |
How it’s formed |
| New snow |
Powder, rime, graupel, etc. |
No two are alike |
On the snow surface |
Falls from the sky |
| Rounded snow |
Equilibrium snow
Old Snow
|
Fine-grained, chalky |
Old layers of snow |
Low temperature gradient conditions
(less than 1 deg C per 10 cm) |
| Faceted Snow |
Sugar Snow
Kinetic Snow
Depth Hoar (when near the ground)
|
Sparkly, large-grained |
Anywhere in the snowpack |
Large temperature gradient conditions
within the snowpack (more than 1 deg C per 10 cm) |
| Surface Hoar |
Frost,
Feathers
|
Sparkly, large-grained |
On the snow surface or buried by more
recent layers |
Winter equivalent of dew on the snow
surface |
| Melt-Freeze Snow |
Corn snow
Spring snow
Wet snow
|
Corn snow
Spring snow
Wet snow
|
Snow surface or buried by more recent
layers |
Repeated melting and freezing of the
snowpack |
|
|
