A Quarterly Activity Bulletin of The South Carolina Department
of Natural Resources-Southeast Regional Climate Center
Volume 6, No. 4
How does snow form?
Snow crystals form when a cloud precipitates and the temperature is at freezing
or below. Just as rain forms when water molecules collect on dust particles
within the cloud, snow forms as well into partly melted crystals. These crystals
accumulate and form snowflakes.
The Bergeron Process
The Bergeron process involves the exchange of molecules between water droplets
in a cloud and an ice crystal. The ice crystal attracts water vapor molecules
from the droplet, and grows in size. This is a part of the crystal formation
process that makes snowflakes.
For more information on the Bergeron Process, click here,
Where Snow Occurs
Snow is surprisingly not bound by a particular region. It can occur in any place
as long as the air temperature falls to freezing or below and there is moisture
in the air. For a map of us accumulated snowfall in the U.S., click on the
Colorado State University Department of Atmospheric Science link here.
Snow can be described in a variety of ways. Every region has its own terminology
for snow and snow events. Identifying the "type" of snow that occurs
where you live can be fascinating.
Snow Terms and Definitions
||mass of loosened snow, ice, and/or earth suddenly and swiftly sliding down a
||a severe weather condition characterized by low temperatures, winds 35 mph
or greater, and sufficient falling and/or blowing snow in the air to that
||snow that looks like large, corn kernel size granules usually occurring in
||snow from a convective cumulus- type cloud and characterized by the
suddenness with which they start and stop.
||rain that falls as liquid and freezes upon impact to form a coating of glaze
on cold surfaces.
||covering of ice crystals that forms by direct sublimation on exposed
surfaces whose temperature is below freezing.
||precipitation which looks like round pellets and is subject to rolling and
can collect in pockets. It can also form a layer with a great deal of pore space
and poor bonding. The pellets themselves are snowflakes which accumulated rime
ice as they fell through certain atmospheric layers.
||precipitation that originates in convective clouds in the form of balls or
irregular pieces of ice and comes in different shapes and sizes, but must have a
diameter of at least 5mm.
||when snow becomes firmly packed. Often snow that has never melted or
||ice crystals formed when water vapor condenses directly into the solid phase
onto a very cold surface.
||hard, glazed surface created by freezing rain, rapid freezing temperatures
and/or saturation from ground water seeping up into the snow and freezing.
||slowly falling ice needles, columns, or plates. Make up cirriform clouds,
frost, and ice fog.
||severe weather condition characterized by freezing rain/ice. Forms a glaze
||any accumulation of snow over an existing surface.
||snow that has been packed down and no longer fluffy, but not hard snow
||cold, new, loose, fluffy dry snow that has not been compacted. Ideal for
||supercooled water droplets which have frozen onto any surface.
||small bits or pellets of ice that rebound after striking the ground or any
other hard surface.
||snow or ice on the ground that has been reduced to a softy watery mixture by
rain and/or warm temperatures.
||smooth rounded deposit of transported snow.
||snow that has become moist due to thaw/rainfall or had a high moisture
content when it fell.
Links to Other Snow Terms
You may have heard that no two snowflakes are alike. That can be debated, but
there are certain shapes that snowflakes tend into. There are several different
classification schemes (click here
to go to the Caltech page and read more), but the six basic shapes are:
needles, columns, plates, dendrites, plate-capped columns, and irregular. A
crystal's shape depends on the air temperature and humidity that occurrs while
the crystal is forming. When it is colder, the snowflakes are smaller and when
the temp is closer to 32° F, the flakes are larger.
These fragile flakes can be used for things other than building forts, snowmen
and sledding. They can also be part of a well-balanced diet! Below are links to
interesting recipes that go beyond simply eating a handful of the fluffy white
IMPORTANT: make sure you use clean fresh snow when you try these.
Question: When was the first snowboard invented?
Answer: Nineteen _ _ _ _ _ _ _ _ _ _ .
Go through through the maze and identify what each picture is. The picture will
correspond with a term from this lesson. Write the term in the appropriate blank
below. When you finish the maze, you will see the answer to the question above
spelled out in the boxed letters.
HINT: you may have to backtrack to hit all of the pictures
For more about snowboarding and its history, click here.
Permission is granted for the reproduction of materials contained in this
Every effort has been made to ensure the accuracy of websites linked to by
SERCC web pages. However, the SERCC/SC DNR are not responsible for the
contents of any "off-site" web pages referenced from the DNR server.
Southeast Regional Climate Center
SC Department of Natural Resources
1201 Main Street, Suite 1100
Columbia, South Carolina 29201
The South Carolina Department of Natural Resources prohibits discrimination
on the basis of race, color, sex, national origin, disability, religion, or age.
Direct all inquiries to the Office of Human Resources, P.O. Box 167, Columbia,