On 10/12/17 11:27, Norman Lynagh wrote:
wrote:

On Sunday, 10 December 2017 11:07:17 UTC, Graham P Davis wrote:
High Wycombe has been reporting this nonsense for hours. Sigh!

--
Graham P Davis, Bracknell, Berks. Web-site:
http://www.scarlet-jade.com/ "Nobody can get the truth out of me
because even I don't know what it is. I keep myself in a constant
state of utter confusion." [Col. Flagg] OS: Linux [openSUSE
Tumbleweed]

You're quite right, as an ex-observer heavy snow would mean a
visibility of a 1000 metres or less.

In Tideswell, I find that moderate snow often reduces visibility to
300-500m. Heavy snow would almost always have a vis of less than 300m.

Heavy snow is defined as snow accumulating at a rate of more than 4
cm/hr. That doesn't often happen here.


When I started observing at Wyton, the guidelines I was given was 1500m
or below for moderate snow and 200m for heavy.

The heaviest snow I've seen reduced the visibility below 50m - a bit
daunting when you're just having to start driving from Stowmarket to
Stansted for a night shift! There had been about 10cm accumulated at
Stowmarket in less than an hour.

The heaviest snow back at my old home of Rushden was an average of 15cm
per hour over a 4 hour period. I missed that as I was at Bracknell.

--
Graham P Davis, Bracknell, Berks. Web-site: http://www.scarlet-jade.com/
"Nobody can get the truth out of me because even I don't know what it
is. I keep myself in a constant state of utter confusion." [Col. Flagg]
OS: Linux [openSUSE Tumbleweed]