Alan White wrote:

On Sun, 6 Feb 2005 10:35:40 -0000, "John DH"
wrote:

...even white-out in the west at times,...

The term 'white out' is one that is becoming greatly misused and seems
to imply, in simple terms, snowing very heavily. Provided that snow is
lying, it's possible to experience a white out without any snow
falling at all. All it needs is lying snow and mist sufficiently dense
to provide omni directional lighting conditions such that no shadows
are visible and the shape and form of the ground underfoot cannot be
determined.

I've only experienced a true white out once, on the summit of Beinn
Narnain (848m), and it was quite interestingly scary. My partner
appeared to be suspended in space, because ground and mist merged
seamlessly, and even foot prints in 10cms of snow were invisible.
Navigation, with a complete absence of any sort of landmark, was
interesting to say the least.

I would hate to think that a phenomenon that is quite rare was being
dumbed down to something that occurs relatively frequently.


Agreed. I first came across the term about 50 years ago in my /Observer's
Book of Weather/ but have never seen the phenomena. Since I can't find the
reference in that book I'll have to make do with the following from the Met
Glossary, 1972.

White-out: A term applied to that condition in which the contours and
natural landmarks in a snow-covered region become indistinguishable. The
associated meteorological conditions appear to be a uniform layer of
relatively low cloud; under such conditions the light which reaches the
surface arrives in nearly equal measure from all directions, with a
resulting absence of shadows,

Graham