I have been struck over the last few days by the huge difference between snow cover at the top of Hampstead Heath (380 feet ASL) and nearby but slightly lower locations such as Swiss Cottage. Although the top of the Heath is generally a little snowier than nearby lower spots, for the recent snow event the difference has been remarkable. At the top of the Heath near the car park behind Jack Straw's Castle, the snow depth has been a consistent 5-8cm since Monday morning (11th) with trees and shrubs plastered in snow even until this morning. It is a true winter scene. Only a few hundreds yard away where we live at a height of about 250 feet, the snow has been 2-3 cm in depth with the trees losing their cover from Tuesday. Down in Swiss Cottage, no more than 1.5 miles from the top of the heath at a height of about 180 feet, there is now scarcely any snow to be seen. Other parts of London are now similarly snowless. I presume the difference is attributable to a combination of the lapse rate, orographic uplift and fewer buildings. Still, it is rather remarkable given the relatively small altitude differences involved.

On Wednesday, February 13, 2013 4:28:06 PM UTC, wrote:
I have been struck over the last few days by the huge difference between snow cover at the top of Hampstead Heath (380 feet ASL) and nearby but slightly lower locations such as Swiss Cottage. Although the top of the Heath is generally a little snowier than nearby lower spots, for the recent snow event the difference has been remarkable. At the top of the Heath near the car park behind Jack Straw's Castle, the snow depth has been a consistent 5-8cm since Monday morning (11th) with trees and shrubs plastered in snow even until this morning. It is a true winter scene. Only a few hundreds yard away where we live at a height of about 250 feet, the snow has been 2-3 cm in depth with the trees losing their cover from Tuesday. Down in Swiss Cottage, no more than 1.5 miles from the top of the heath at a height of about 180 feet, there is now scarcely any snow to be seen. Other parts of London are now similarly snowless. I presume the difference is attributable to a combination of the lapse rate, orographic uplift and fewer buildings. Still, it is rather remarkable given the relatively small altitude differences involved.

It is the same in High Wycombe. I still have several cms of snow in my back garden at roughly 175m. About a quarter of mile away down the hill a bit there is little cover, Altitude about 50m lower there.

Paul Kendall

wrote in message
...
I have been struck over the last few days by the huge difference between
snow cover at the top of Hampstead Heath (380 feet ASL) and nearby but
slightly lower locations such as Swiss Cottage. Although the top of the
Heath is generally a little snowier than nearby lower spots, for the recent
snow event the difference has been remarkable. At the top of the Heath near
the car park behind Jack Straw's Castle, the snow depth has been a
consistent 5-8cm since Monday morning (11th) with trees and shrubs plastered
in snow even until this morning. It is a true winter scene. Only a few
hundreds yard away where we live at a height of about 250 feet, the snow has
been 2-3 cm in depth with the trees losing their cover from Tuesday. Down in
Swiss Cottage, no more than 1.5 miles from the top of the heath at a height
of about 180 feet, there is now scarcely any snow to be seen. Other parts of
London are now similarly snowless. I presume the difference is attributable
to a combination of the lapse rate, orographic uplift and fewer buildings.
Still, it is rather remarkable given the relatively small altitude
differences involved.

=========================

Yes it is called the "snow line" for good reason. It actually is a
horizontal line. More noticeable admittedly in very hilly/mountain areas but
will be there at an level. Last month the snow line in my area was at circa
100 metres asl, today it would be above the summits. Cities do add a
complication as you suggest in that the additional urban heat will tend to
melt snow faster obviously. Above the snow line amounts will vary depending
on where the wet-bulb freezing level was when it started snowing. The
deepest snow will be from 100 metres above the wet-bulb freezing level
upwards. Fascinating post, many thanks. It will be all gone by this time
tomorrow though.

Will
--
http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
---------------------------------------------

On 13/02/2013 16:28, wrote:
I have been struck over the last few days by the huge difference between snow cover at the top of Hampstead Heath (380 feet ASL) and nearby but slightly lower locations such as Swiss Cottage. Although the top of the Heath is generally a little snowier than nearby lower spots, for the recent snow event the difference has been remarkable. At the top of the Heath near the car park behind Jack Straw's Castle, the snow depth has been a consistent 5-8cm since Monday morning (11th) with trees and shrubs plastered in snow even until this morning. It is a true winter scene. Only a few hundreds yard away where we live at a height of about 250 feet, the snow has been 2-3 cm in depth with the trees losing their cover from Tuesday. Down in Swiss Cottage, no more than 1.5 miles from the top of the heath at a height of about 180 feet, there is now scarcely any snow to be seen. Other parts of London are now similarly snowless. I presume the difference is attributable to a combination of the lapse
rate, orographic uplift and fewer buildings. Still, it is rather remarkable given the relatively small altitude differences involved.


As a student in the late 1960's I lived in Hampstead for a year. I
recall heavy snowfalls in December 1967 and January 1968 when there was
up to 30cm of snow (1968) in the highest parts of Hampstead but far less
lower down. Same in many similar areas (e.g. Epping) and shows what a
marginal phenomenon all this snow business is away from the upland areas
of the North and West.
--
George in Epping, west Essex, 350'asl
www.eppingweather.co.uk
www.winter1947.co.uk

I have been struck over the last few days by the huge difference between
snow cover at the top of Hampstead Heath (380 feet ASL) and nearby
Similar in my area (mid Shropshire) where ground above 150-160m has been
snow covered since Sunday afternoon, whereas at my altitude (just above
100m) any cover has been fleeting and reluctant.
--
Freddie
Bayston Hill
Shropshire
102m AMSL
http://www.hosiene.co.uk/weather/
https://twitter.com/#!/BaystonHillWx for hourly reports

On Feb 13, 4:28*pm, wrote:
I have been struck over the last few days by the huge difference between snow cover at the top of Hampstead Heath (380 feet ASL) and nearby but slightly lower locations such as Swiss Cottage. Although the top of the Heath is generally a little snowier than nearby lower spots, for the recent snow event the difference has been remarkable. At the top of the Heath near the car park behind Jack Straw's Castle, the snow depth has been a consistent 5-8cm since Monday morning (11th) with trees and shrubs plastered in snow even until this morning. It is a true winter scene. Only a few hundreds yard away where we live at a height of about 250 feet, the snow has been 2-3 cm in depth with the trees losing their cover from Tuesday. Down in Swiss Cottage, no more than 1.5 miles from the top of the heath at a height of about 180 feet, there is now scarcely any snow to be seen. Other parts of London are now similarly snowless. I presume the difference is attributable to a combination of the lapse rate, orographic uplift and fewer buildings. Still, it is rather remarkable given the relatively small altitude differences involved.

The urban heat island effect has also been stark this week. Where I
live in Aldersbrook, just south of Wanstead, has retained the snow far
better than the immediate surrounding areas, even though it is only
18m asl. Though it is only 7 miles from the City it is surrounded by
very open green space - almost making it semi-rural, with Wanstead
Flats to the south, the City of London cemetary to the east, and
Wanstead Park to the north, and Bushwood to the west, the estate is a
bit of an island in green. The easterly feed has also helped - with no
obvious warming from central London. Still quite a few patches left.

On 13/02/13 16:28, wrote:
I have been struck over the last few days by the huge difference between snow cover at the top of Hampstead Heath (380 feet ASL) and nearby but slightly lower locations such as Swiss Cottage. Although the top of the Heath is generally a little snowier than nearby lower spots, for the recent snow event the difference has been remarkable. At the top of the Heath near the car park behind Jack Straw's Castle, the snow depth has been a consistent 5-8cm since Monday morning (11th) with trees and shrubs plastered in snow even until this morning. It is a true winter scene. Only a few hundreds yard away where we live at a height of about 250 feet, the snow has been 2-3 cm in depth with the trees losing their cover from Tuesday. Down in Swiss Cottage, no more than 1.5 miles from the top of the heath at a height of about 180 feet, there is now scarcely any snow to be seen. Other parts of London are now similarly snowless. I presume the difference is attributable to a combination of th
e lapse rate, orographic uplift and fewer buildings. Still, it is rather remarkable given the relatively small altitude differences involved.

When I went to Bristol on the 23rd January and walked from the railway
station to my hotel near the university (about 1.5 miles and a steady
climb), I went from snow but no settling to an inch on the ground and
slippery underfoot.

On Wed, 13 Feb 2013 16:57:43 -0000
"Eskimo Will" wrote:


wrote in message
...
I have been struck over the last few days by the huge difference
between snow cover at the top of Hampstead Heath (380 feet ASL) and
nearby but slightly lower locations such as Swiss Cottage. Although
the top of the Heath is generally a little snowier than nearby lower
spots, for the recent snow event the difference has been remarkable.
At the top of the Heath near the car park behind Jack Straw's Castle,
the snow depth has been a consistent 5-8cm since Monday morning
(11th) with trees and shrubs plastered in snow even until this
morning. It is a true winter scene. Only a few hundreds yard away
where we live at a height of about 250 feet, the snow has been 2-3 cm
in depth with the trees losing their cover from Tuesday. Down in
Swiss Cottage, no more than 1.5 miles from the top of the heath at a
height of about 180 feet, there is now scarcely any snow to be seen.
Other parts of London are now similarly snowless. I presume the
difference is attributable to a combination of the lapse rate,
orographic uplift and fewer buildings. Still, it is rather remarkable
given the relatively small altitude differences involved.

=========================

Yes it is called the "snow line" for good reason. It actually is a
horizontal line. More noticeable admittedly in very hilly/mountain
areas but will be there at an level. Last month the snow line in my
area was at circa 100 metres asl, today it would be above the
summits. Cities do add a complication as you suggest in that the
additional urban heat will tend to melt snow faster obviously. Above
the snow line amounts will vary depending on where the wet-bulb
freezing level was when it started snowing. The deepest snow will be
from 100 metres above the wet-bulb freezing level upwards.
Fascinating post, many thanks. It will be all gone by this time
tomorrow though.


It suggests that the snow-line has changed very little in height over
several days; if it had moved up and down more, the change in snow
cover in the vertical would have been much more gradual.

--
Graham P Davis, Bracknell, Berks.
Feeling stressed and frustrated? Try a short session of contemplative
meditation. Or kick a ballboy. (https://twitter.com/GreySkyThinking)