A friend of mine experienced a very strong dust devil (or something
similar). It was on Wednesday 25th of July at about 2.0pm. It happened
in a field near the A 27 near to The Longman at what used to be
Longman's Nurseries about three miles outside Eastbourne.
The sky was clear blue. Two big plastic tubs were taken right across the
field and rubbish swirled around high in the sky. One green canvas tent
was taken down and the contents of another, which had its end flaps open
were tossed and turned around with two sleeping mats whisked out of the
tent and up into the sky over the field and out of sight. Two heavier
sleeping bags were taken up too but dropped back down again about 25
yards away. They weren't able to recover the mats as they went far away
across the road at the bottom of the field. A play tent was blown up
into the sky and fell about 200 yards down the lane.
Has anyone any idea what might have caused it; the field was of grass,
and it seems strange that such a thing could form over grass. There is a
photograph of paper rubbish which has been blown quite high gently
drifting down. Unfortunately the photos are only of the results not the
devil itself - it was strong enough to deter my friend from rushing to
get her camera.

On Wed, 01 Aug 2012 22:42:30 +0100, Metman2012
wrote:

A friend of mine experienced a very strong dust devil (or something
similar). It was on Wednesday 25th of July at about 2.0pm. It happened
in a field near the A 27 near to The Longman at what used to be
Longman's Nurseries about three miles outside Eastbourne.
The sky was clear blue. Two big plastic tubs were taken right across the
field and rubbish swirled around high in the sky. One green canvas tent
was taken down and the contents of another, which had its end flaps open
were tossed and turned around with two sleeping mats whisked out of the
tent and up into the sky over the field and out of sight. Two heavier
sleeping bags were taken up too but dropped back down again about 25
yards away. They weren't able to recover the mats as they went far away
across the road at the bottom of the field. A play tent was blown up
into the sky and fell about 200 yards down the lane.
Has anyone any idea what might have caused it; the field was of grass,
and it seems strange that such a thing could form over grass. There is a
photograph of paper rubbish which has been blown quite high gently
drifting down. Unfortunately the photos are only of the results not the
devil itself - it was strong enough to deter my friend from rushing to
get her camera.

We get them frequently. - Lincolnshire.

Last week our field had been hay cut and it was drying out after
turning. Quite a few devils went through, small about 10 to 15ft dia.

I suppose it is a thermal that gets set revolving.

Jeff

"Jeff" wrote in message
...
On Wed, 01 Aug 2012 22:42:30 +0100, Metman2012
wrote:

A friend of mine experienced a very strong dust devil (or something
similar). It was on Wednesday 25th of July at about 2.0pm. It happened
in a field near the A 27 near to The Longman at what used to be
Longman's Nurseries about three miles outside Eastbourne.
The sky was clear blue. Two big plastic tubs were taken right across the
field and rubbish swirled around high in the sky. One green canvas tent
was taken down and the contents of another, which had its end flaps open
were tossed and turned around with two sleeping mats whisked out of the
tent and up into the sky over the field and out of sight. Two heavier
sleeping bags were taken up too but dropped back down again about 25
yards away. They weren't able to recover the mats as they went far away
across the road at the bottom of the field. A play tent was blown up
into the sky and fell about 200 yards down the lane.
Has anyone any idea what might have caused it; the field was of grass,
and it seems strange that such a thing could form over grass. There is a
photograph of paper rubbish which has been blown quite high gently
drifting down. Unfortunately the photos are only of the results not the
devil itself - it was strong enough to deter my friend from rushing to
get her camera.

We get them frequently. - Lincolnshire.

Last week our field had been hay cut and it was drying out after
turning. Quite a few devils went through, small about 10 to 15ft dia.

I suppose it is a thermal that gets set revolving.


Yes the larger ones can be quite alarming.

Will
--

On Wed, 01 Aug 2012 22:42:30 +0100, Metman2012 wrote:

A friend of mine experienced a very strong dust devil (or something
similar). It was on Wednesday 25th of July at about 2.0pm. It happened
in a field near the A 27 near to The Longman at what used to be
Longman's Nurseries about three miles outside Eastbourne.
The sky was clear blue. Two big plastic tubs were taken right across the
field and rubbish swirled around high in the sky. rest snipped

.... witnessed one of these back in the early 1980s in Finningley village
(I was stationed at RAF Finningley & we lived in the village); my wife
and I were helping out at the local village fête and it was a fine day
with shallow Cu hum - plenty of blue sky, a gentle (F3,ocnl F4) wind
from WSW (in which direction lay the aforementioned airfield - a vast
expanse of short-mown grass and lots of concrete/tarmac).

The field being used for the fête was directly downwind of the airfield
with little or no physical barrier to anything coming along from that
direction (the hedges were either non-existent or kept cut deliberately
low to aid security).

We had just got the stalls set up, covered, laid out etc., when I became
aware of a swirl of dust approaching from the airfield - it crossed
directly over the fête area - several tables completely over-turned,
many others having contents thrown aside and causing no little angst!
Fortunately, within 90 seconds, it had gone, we all dusted ourselves
down and re-set the stalls. I should think that the wind achieved at
least F7 for a short time.

Strong surface heating - steep lapse rate in the lowest tens of feet -
and neutral stability above (or the energy tends to get dispersed
vertically without causing other than a 'normal' gust).

I think I wrote it up in a 'Weather' at the time, but can't remember now
- and they've all gone unfortunately.

Martin.



--
West Moors / East Dorset
Lat: 50deg 49.25'N, Long: 01deg 53.05'W
Height (amsl): 17 m (56 feet)
COL category: C1 overall

"Martin Rowley" wrote in message
...
On Wed, 01 Aug 2012 22:42:30 +0100, Metman2012 wrote:

A friend of mine experienced a very strong dust devil (or something
similar). It was on Wednesday 25th of July at about 2.0pm. It happened
in a field near the A 27 near to The Longman at what used to be
Longman's Nurseries about three miles outside Eastbourne.
The sky was clear blue. Two big plastic tubs were taken right across
the
field and rubbish swirled around high in the sky. rest snipped

... witnessed one of these back in the early 1980s in Finningley village
(I was stationed at RAF Finningley & we lived in the village); my wife and
I were helping out at the local village fête and it was a fine day with
shallow Cu hum - plenty of blue sky, a gentle (F3,ocnl F4) wind from WSW
(in which direction lay the aforementioned airfield - a vast expanse of
short-mown grass and lots of concrete/tarmac).

The field being used for the fête was directly downwind of the airfield
with little or no physical barrier to anything coming along from that
direction (the hedges were either non-existent or kept cut deliberately
low to aid security).

We had just got the stalls set up, covered, laid out etc., when I became
aware of a swirl of dust approaching from the airfield - it crossed
directly over the fête area - several tables completely over-turned, many
others having contents thrown aside and causing no little angst!
Fortunately, within 90 seconds, it had gone, we all dusted ourselves down
and re-set the stalls. I should think that the wind achieved at least F7
for a short time.

Strong surface heating - steep lapse rate in the lowest tens of feet - and
neutral stability above (or the energy tends to get dispersed vertically
without causing other than a 'normal' gust).

I think I wrote it up in a 'Weather' at the time, but can't remember now -
and they've all gone unfortunately.

Martin.


"Weather" is available online at Met Office website. However, I think you
may have to subscribe.
MetO employees can get all the science literature online. One can always pop
into the MetO library physically though, bit difficult, however, if you live
a long way away from the near centre of the universe :-)
Martin I was at Finningley 1970-1971.

Will
--

... witnessed one of these back in the early 1980s in Finningley village
....
I think I wrote it up in a 'Weather' at the time, but can't remember now .... Martin

Weather, May 1994, Vol. 49, p. 192, Letters to the Editor:
"Dust Devils ... As an example, I should like to relate the following personal experience. On 18 August 1984, my wife and I attended a local fête in the village of Finningley, South Yorkshire, hard by the RAF airfield of the same name, where I was then stationed ... (etc) ... M.G. Rowley, St Albans, Hertfordshire."

I have a PDF scan of that edition of "Weather" here on my computer. I can send you a copy of the whole letter by e-mail, if you want.

Colin Youngs
Brussels

On 02/08/2012 09:48, Martin Rowley wrote:
On Wed, 01 Aug 2012 22:42:30 +0100, Metman2012 wrote:

A friend of mine experienced a very strong dust devil (or something
similar). It was on Wednesday 25th of July at about 2.0pm. It happened
in a field near the A 27 near to The Longman at what used to be
Longman's Nurseries about three miles outside Eastbourne.
The sky was clear blue. Two big plastic tubs were taken right across
the
field and rubbish swirled around high in the sky. rest snipped

... witnessed one of these back in the early 1980s in Finningley village
(I was stationed at RAF Finningley & we lived in the village); my wife
and I were helping out at the local village fête and it was a fine day
with shallow Cu hum - plenty of blue sky, a gentle (F3,ocnl F4) wind
from WSW (in which direction lay the aforementioned airfield - a vast
expanse of short-mown grass and lots of concrete/tarmac).

The field being used for the fête was directly downwind of the airfield
with little or no physical barrier to anything coming along from that
direction (the hedges were either non-existent or kept cut deliberately
low to aid security).

We had just got the stalls set up, covered, laid out etc., when I became
aware of a swirl of dust approaching from the airfield - it crossed
directly over the fête area - several tables completely over-turned,
many others having contents thrown aside and causing no little angst!
Fortunately, within 90 seconds, it had gone, we all dusted ourselves
down and re-set the stalls. I should think that the wind achieved at
least F7 for a short time.

Strong surface heating - steep lapse rate in the lowest tens of feet -
and neutral stability above (or the energy tends to get dispersed
vertically without causing other than a 'normal' gust).

I think I wrote it up in a 'Weather' at the time, but can't remember now
- and they've all gone unfortunately.

Martin.


Members of the Royal Met Soc can now access scanned copies of Weather
all the way back to 1946. As I recall it was necessary to re-register on
the Royal Met Soc website and after that it was into pure nostalgia.

--
George in Epping
www.eppingweather.co.uk
www.winter1947.co.uk

On 02/08/2012 16:02, Colin Youngs wrote:
... witnessed one of these back in the early 1980s in Finningley village
...
I think I wrote it up in a 'Weather' at the time, but can't remember now ... Martin

Weather, May 1994, Vol. 49, p. 192, Letters to the Editor:
"Dust Devils ... As an example, I should like to relate the following personal experience. On 18 August 1984, my wife and I attended a local fête in the village of Finningley, South Yorkshire, hard by the RAF airfield of the same name, where I was then stationed ... (etc) ... M.G. Rowley, St Albans, Hertfordshire."

I have a PDF scan of that edition of "Weather" here on my computer. I can send you a copy of the whole letter by e-mail, if you want.

Colin Youngs
Brussels

.... Thanks Colin: it's not important for me so much but others may like
the reference in case they want to look it up.

Martin.



--
West Moors / East Dorset
Lat: 50deg 49.25'N, Long: 01deg 53.05'W
Height (amsl): 17 m (56 feet)
COL category: C1 overall

On Wednesday, 1 August 2012 22:42:30 UTC+1, Metman2012 wrote:
A friend of mine experienced a very strong dust devil (or something

similar). It was on Wednesday 25th of July at about 2.0pm. It happened

in a field near the A 27 near to The Longman at what used to be

Longman's Nurseries about three miles outside Eastbourne.

The sky was clear blue. Two big plastic tubs were taken right across the

field and rubbish swirled around high in the sky. One green canvas tent

was taken down and the contents of another, which had its end flaps open

were tossed and turned around with two sleeping mats whisked out of the

tent and up into the sky over the field and out of sight. Two heavier

sleeping bags were taken up too but dropped back down again about 25

yards away. They weren't able to recover the mats as they went far away

across the road at the bottom of the field. A play tent was blown up

into the sky and fell about 200 yards down the lane.

Has anyone any idea what might have caused it; the field was of grass,

and it seems strange that such a thing could form over grass. There is a

photograph of paper rubbish which has been blown quite high gently

drifting down. Unfortunately the photos are only of the results not the

devil itself - it was strong enough to deter my friend from rushing to

get her camera.

I think they are a reaction to temperature inversions breaking down in very still layers of atmosphere. In northern Canada and Russia where the snow lies thick under pine trees yet the spring is well along, the air above the canopy can be very warm and yet under the trees very cold.

Similarly in lower latitudes the air on the surface can be warm and higher up of fairly varied temperature.

Then something disturbs the layers and the air erupts. Then they are contained by the surrounding air whose pressure/temperatures are constant. The result is that the air must rise since it is blocked from the sides and from below.

Once risen, there is now a change in the pressure that adjacent air has to fill.

There was a thread on here about 2 or 3 months ago discussing how a larger more powerful vortex behaves. And how it could be replicated in a bottle. Which of course it can't, due to the need for the surrounding air in the real thing to act as a container for the vortex.

On 02/08/2012 16:02, Colin Youngs wrote:
... witnessed one of these back in the early 1980s in Finningley village
...
I think I wrote it up in a 'Weather' at the time, but can't remember now ... Martin

Weather, May 1994, Vol. 49, p. 192, Letters to the Editor:
"Dust Devils ... As an example, I should like to relate the following personal experience. On 18 August 1984, my wife and I attended a local fête in the village of Finningley, South Yorkshire, hard by the RAF airfield of the same name, where I was then stationed ... (etc) ... M.G. Rowley, St Albans, Hertfordshire."

I have a PDF scan of that edition of "Weather" here on my computer. I can send you a copy of the whole letter by e-mail, if you want.

Colin Youngs
Brussels

Colin, is it possible to send me a copy please - I can then pas it on to
my friend. Not sure about copyright, so not a problem if you can't.

Malcolm