Almost all of the light is reflected or scattered by the air and water molecules so the snow appears to be the color of sunlight white.
White light source spectrum.
White light can be generated by a variety of sources both in space and by artificial sources on earth.
The frequency of light that we see as red is being reflected and we see that shirt as red.
Figure 1 shows the spds of two electric light sources claimed to be full spectrum the duro test vita lite 5500 fluorescent lamp and ge reveal 60w incandescent lamp as well as daylight at 5500k correlated color temperature cct.
However it was the invention of the blue led that led to the creation of new efficient white light sources.
By scanning changing the measurement beam path length relative to the reference beam a correlogram is generated at each pixel.
Black and white are a bit different from other colors.
Blue light emitted from such leds can be used to stimulate a wider spectrum of emission from a phosphor layer around the led casing or can be directly combined with red and green leds to create white light.
The sun is the most obvious.
The interference occurs for white light when the path lengths of the measurement beam and the reference beam are nearly matched.
White is a combination of all colors so when we see white the object is reflecting all the colors of light the same.
Sometimes the light bounces around inside the ice crystals before being scattered making the snow seem to sparkle.
For example the sun and other stars are sources of white light.
The width of the resulting correlogram is the coherence length which depends strongly on the spectral width of the light source.