Color
Snow is white, but why? The appearance of objects are due to the
frequencies of visible light that they absorb, but there are other
factors that play a role in their color. Fresh snow reflects
sunlight, thus giving it a white color. However, its perceived color
may change based on other factors.
Watermelon snow (nsidc.org)
Factors affecting snow color: Absorbed frequencies - The frequencies
absorbed by the object determines its color. Fresh snow reflects
sunlight, thus white in
appearance. Other frequencies may be absorbed,
but the 'preferred' color 'wins.'
Distance light travels - As light
travels into snow, ice particles must scatter the light so that it
is not absorbed. The deeper the
distance traveled by the light, it often assumes
a blue color--it's preferential. For instance, if a deep hole is
poked into a snow,
the inside might look blue.
Particles or organisms - Particles (especially
dark colored) and organism residing in the snow could change snow's
color.
For instance, dust and soot absorb more sunlight,
causing it to look dark. The watermelon snow shown above has a pink
hue
due to the fresh-water algae with bright red pigment
that resides in it.
Sound
Snow can affect sound waves by enhancing or dampening them depending
on its characteristics and age. Sound is dampened with thick, fresh,
and fluffy snow by absorbing sound waves. On the contrary, smooth
and hard snow enhances sound by reflects sound waves, allowing them
to travel at a farther distance.
Insulation
Snow is a good insulator which is why some animals use them during
the winter for hibernation or habitat. The surface of snow pack's
temperature is affected by the ambient temperature, but snow closer
to the ground are warmer. Heat from the ground slowly dissipates due
to snow serving as a 'barrier' or insulator, decreasing the rate of
heat exchange with the cold air on the surface. Freshly dropped snow
also has a high composition of air--about 90 to 95%. The combination
of insulation and oxygen availability allows some animals to
hibernate in snow caves or tunnels without dying from cold ambient
temperatures; the space between the ground and the surface of the
snow pack is called the subnivean zone. Examples of animals that
live in the subnivean zone include mice, shrews, squirrels, etc. of
specific species.
