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Avalanche Hazard Forecast - do you understand it?

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Jhimmy

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Dec 30, 2009, 9:22:22 AM12/30/09
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Am I the only person to get confused by new the "Dart Board" Avalanche
reports for Scotland?

http://www.sais.gov.uk/

I know it was approved by all the experts, MRT, Police etc. after a term of
consultation. I am NOT an expert just a walker. But what the hell does it
tell you? Where is the bullseye centred on? I find it more confusing then
informative. As the outer ring starts at the snowline, it changes so as you
get used to 300m, the damn thing might change to 600m without you taking
notice. Is this a case of "dumming down" instead of a telling you exactly
where the danger is?

I'll be interested in what others think.

Jhimmy

Alan Dicey

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Dec 30, 2009, 10:21:29 AM12/30/09
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I read it as a general forecast for the whole area. Take the six
o'clock slice: it's telling you the danger of avalanche on all
south-facing slopes in the area, and gives two zones, low and high,
between snowline and highest elevation in the area.

Phil Cook

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Dec 30, 2009, 10:21:27 AM12/30/09
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Jhimmy wrote:

OK I'm game.

Opened up the SAIS site and clicked on Creag Meggy.

What the!!!!

Then clicked for full report and can see where they are coming from.

The rings are for altitude and the sectors for aspect. The rings will
change with respect to conditions I think.

The slightly anoying thing is that the obsevations are on a separate
screen :-( But you can get it together on the PDF download.
--
Phil Cook, last hill: Cadair Idris in the mist.
http://www.therewaslight.co.uk

Dominic Sexton

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Dec 30, 2009, 10:26:15 AM12/30/09
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In article <ymJ_m.7401$vI7....@newsfe29.ams2>, Jhimmy
<cobalt...@yahoo.com> writes

It is a graphical representation of the hazard.

The centre is irrelevant. It is showing you what the hazard level is in
terms of slope aspect for the general area. They may also indicate a
potential localised hazard with a higher level dot in an otherwise lower
level sector.

I think it is a good summary and easy to remember when on the hill. You
should be able visualise the diagram and just have to remember the
altitude where the hazard changes, if applicable. That way you will
hopefully recall that e.g. the hazard level is higher on S/SW facing
slopes above 800m. Much easier to remember than text which is especially
important if your plans for the day change while on the hill.

--

Dominic Sexton

Chris Gilbert

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Dec 30, 2009, 3:25:27 PM12/30/09
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Jhimmy wrote

> I'll be interested in what others think.

I think that's pretty darn good, actually. At a glance altitude, aspect
and risk level. Of course you factor in local circumstances and relief
but that is a very good way of presenting the risk pictorially. It has
to be accompanied by a written synopsis simply because some people
tend toward written analysis while others prefer a visual representation.
Good bit of work that, IMO.

Chris
--
Photography by Chris Gilbert
www.ravenseyegallery.co.uk
Graphic Services for Holiday Cottage Owners
www.picturemycottage.co.uk


Judith

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Dec 30, 2009, 4:06:14 PM12/30/09
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On Wed, 30 Dec 2009 20:25:27 -0000, "Chris Gilbert"
<ch...@ravenseye.plus.com> wrote:

>
>> I'll be interested in what others think.
>
>I think that's pretty darn good, actually. At a glance altitude, aspect
>and risk level. Of course you factor in local circumstances and relief
>but that is a very good way of presenting the risk pictorially. It has
>to be accompanied by a written synopsis simply because some people
>tend toward written analysis while others prefer a visual representation.
>Good bit of work that, IMO.

I did not understand it, at first glance, and was asking the same
questions that Jhimmy did. However, now that people have explained
it, I can understand it and it seems a reasonable way to portray the
risks and make them easy for people to remember.

Judith

Tom Crispin

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Dec 30, 2009, 6:55:24 PM12/30/09
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On Wed, 30 Dec 2009 14:22:22 -0000, "Jhimmy" <cobalt...@yahoo.com>
wrote:

Think of it with the bull's eye centred on the summit of a hill, now
wrap the diagram around the hill, orientated with north at the top.

Each sector of the chart represents the aspect of the hill from summit
to base.

An excellent easy to read and easy to remember chart.

Simon Challands

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Dec 31, 2009, 6:12:13 AM12/31/09
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In message <eKWdnUvCDse8KqbW...@brightview.co.uk>
"Chris Gilbert" <ch...@ravenseye.plus.com> wrote:

> Jhimmy wrote

>> I'll be interested in what others think.

> I think that's pretty darn good, actually. At a glance altitude, aspect
> and risk level. Of course you factor in local circumstances and relief
> but that is a very good way of presenting the risk pictorially. It has
> to be accompanied by a written synopsis simply because some people
> tend toward written analysis while others prefer a visual representation.
> Good bit of work that, IMO.

I quite like the look of it. Think of it as a contour map of a very
simply-shaped hill and it's showing you where on that hill the risk
is. Of course I'd prefer it if it wasn't in ***** metric like
everything else is these days so that I'm not having to translate the
heights into something meaningful, but you can't have everything.

--
Simon Challands

Surfer!

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Dec 31, 2009, 7:42:21 AM12/31/09
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In message <eKWdnUvCDse8KqbW...@brightview.co.uk>, Chris
Gilbert <ch...@ravenseye.plus.com> writes

>Jhimmy wrote
>
>> I'll be interested in what others think.
>
>I think that's pretty darn good, actually. At a glance altitude, aspect
>and risk level. Of course you factor in local circumstances and relief
>but that is a very good way of presenting the risk pictorially. It has
>to be accompanied by a written synopsis simply because some people
>tend toward written analysis while others prefer a visual representation.
>Good bit of work that, IMO.
>
Today for Lochaber has a yellow sector with an orange dot in it - not
sure how to interpret that. Suggestions?

--
Surfer!

nm...@cam.ac.uk

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Dec 31, 2009, 8:07:32 AM12/31/09
to
In article <wPc0E7+t...@nevis-view.co.uk>,

Surfer! <sur...@127.0.0.1> wrote:
>>
>Today for Lochaber has a yellow sector with an orange dot in it - not
>sure how to interpret that. Suggestions?

Watch out for avalanches of ladybirds.


Regards,
Nick Maclaren.

Chris Gilbert

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Dec 31, 2009, 8:08:56 AM12/31/09
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Surfer! wrote

> Today for Lochaber has a yellow sector with an orange dot in it - not sure
> how to interpret that. Suggestions?

The key states that dots represent localised risk.

Chris


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