2009 - Snow-patches Surviving On Scottish Mountains

[firefly]

Well, we're getting down to the business end of the season now, with only a handful of snow-patches remaining on the high hills of Scotland. Currently 4 mountains with snow-patches, namely: Ben Nevis, Aonach Beag, Aonach Mor & Braeriach.

Of these, Aonach Mor's are almost certain to go by the start of October, but probably sooner. I've not seen Aonach Beag's since the 22nd of August, so don't know how it's fairing. Ben Nevis's snow still in reasonable nick, as you can see from this photograph from a few days ago. The main patch (through the clouds) is in the region of 50m long and wide. The smaller patches to the left (Point 5 Gully) just survived last year, and are in broadly the same nick as last year.

Braeriach's Garbh Choire Mor's snows are down to just 2 patches. These are the last in the Cairngorms, with all other ones having melted last week. I've attached a picture of them (courtesy of Nic Bullivant of Cairngorm Mountain). The patch in the middle (the topmost), Sphinx, is Britain's longest-lying snow, with the ground underneath it being exposed to daylight for fewer than 10-months in the last 100 years.

At the moment it's still too early to say with any certainty which patches will survive. Certainly fewer than 2008, and most likely 2007 as well.

Edited September 14, 2009 by firefly

[cyclonic happiness]

I know this may sound like a silly question but, when does a snow patch become a glacier?

[pinkertonsurly]

I do remember reading an A Level textbook (some time ago) which described the snow patch on Ben Nevis as 'an incipient glacier'. The knife edge conditions mean that any long term change in the various conditions (summer temperature and rainfall, winter snowfall etc) required for its existence, even small ones, could result in its size increasing and permanent status.

[firefly]

Essentially, glaciers form where the accumulation of snow and ice exceeds the melting (or ablation). In reality, this never happens in Scotland. Perhaps if Ben Nevis was 500ft higher then we may have the beginnings of a glacier (or, an incipient one!), but not at present.

Ben Nevis's snowfield is most certainly not an incipient glacier, and nor are any snowfields in Scotland. The average annual temperature would need to fall, according to some estimates, 3 Celcius before we could start talking about incipient glaciers. As it stands, Scotland is too warm and the mountains too low for this to happen anytime soon.

...and before anyone pitches in about glaciers in the Little Ice Age in the Cairngorms(!), there haven't been any in Scotland for thousands of years.

[stewfox]

Essentially, glaciers form where the accumulation of snow and ice exceeds the melting (or ablation). In reality, this never happens in Scotland. Perhaps if Ben Nevis was 500ft higher then we may have the beginnings of a glacier (or, an incipient one!), but not at present.

Ben Nevis's snowfield is most certainly not an incipient glacier, and nor are any snowfields in Scotland. The average annual temperature would need to fall, according to some estimates, 3 Celcius before we could start talking about incipient glaciers. As it stands, Scotland is too warm and the mountains too low for this to happen anytime soon.

...and before anyone pitches in about glaciers in the Little Ice Age in the Cairngorms(!), there haven't been any in Scotland for thousands of years.

I read somewhere to have this to happen the average heights would have to be 7000ft in Scotland

[Terminal Moraine]

I read somewhere to have this to happen the average heights would have to be 7000ft in Scotland

Gorden Manley, in his aged but unsurpassed book, 'Climate and the British Scene' states that calculations done in the early 1950s, and relating to the climate in the 30 years prior to then, indicate that Ben Nevis would have to be higher than about 5,300 ft in order for an incipent glacier to form. The equivalent figures for the Lake District and Snowdon are 5,900 ft and 6,300 ft respectively.

On the basis that summer temperatures over the last 20 years or so are not dramatically different from those in the 20s 30s and 40s I think we can assume that these figures are about right, give or take a couple of hundred feet.

[stewfox]

Gorden Manley, in his aged but unsurpassed book, 'Climate and the British Scene' states that calculations done in the early 1950s, and relating to the climate in the 30 years prior to then, indicate that Ben Nevis would have to be higher than about 5,300 ft in order for an incipent glacier to form. The equivalent figures for the Lake District and Snowdon are 5,900 ft and 6,300 ft respectively.

On the basis that summer temperatures over the last 20 years or so are not dramatically different from those in the 20s 30s and 40s I think we can assume that these figures are about right, give or take a couple of hundred feet.

Happy to be corrected. Always dangerous when you have read something about somewhere in the past.

I always wished Box hill in surrey was 6,500ft and not 650ft. Although as a kid I wouldn't have fancied rolling down it.

Just think how the winter dicussions would change if average heights were 10 times higher

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Just think how the winter dicussions would change if average heights were 10 times higher

Ben Nevis would be about 13,000m asl!

I agree, it would be good if we had 'proper' mountains like in countries such as Switzerland! (like this!)

Edited September 21, 2009 by RAIN RAIN RAIN

[Nick L]

Didn't the Scottish mountains used to be considerably higher millions of years ago? Could have sworn I saw a programme once which said that they have gradually been eroded over the years.

[Cheviot]

Yes - not sure on figure, but quite a bit higher.

I do know that the Lake District and Glencoe were substantially higher. Scafell and the surrounding mountains are small remnants of an ancient super-volcano. The area around Glencoe also holds the remnants of a super-volcano.

Super-volcanos emit enormous amounts of rock over their active life.

The Scafell and Glencoe volcanos had an estimated Volcanic Explosivity Index of 8 (see http://en.wikipedia.org/wiki/Volcanic_Explosivity_Index for further description). This is termed a "mega-collasal" eruptive volcano, and compares with the likes of Yellowstone and Taupo in New Zealand. These are climate controlling volcanoes that can cause global havoc to life. To give some indicator of their size, Mount St Helen's in 1980 erupted 1000 times less material than either of these. Krakatoa and Pinotubo erupted about 40 times less material. These truelly are giants of nature.

Estimating the height of super-volcanoes is difficult because they come in different forms. However, it is likely that 3000-4000m asl was possible. I recall reading somewhere that the mountains of the Caledonian range (of which the Lake District is geologically part of) were Himilayan in size about 450 million years ago. I'm afaid I'm not old enough to qualify this!

Edited September 22, 2009 by Cheviot

[stewfox]

With North Westerlies forecast in the next few days will the higher elevations get their first snow of the season ?

[Nick L]

With North Westerlies forecast in the next few days will the higher elevations get their first snow of the season ?

BBC Weather mentioned it for Thursday morning I think it was.

[Backtrack]

Didn't the Scottish mountains used to be considerably higher millions of years ago? Could have sworn I saw a programme once which said that they have gradually been eroded over the years.

Before Ben Nevis was eroded, they say it would of rivaled Mount Everest in height.

[Moomin]

Before Ben Nevis was eroded, they say it would of rivaled Mount Everest in height.

Yes this is quite probable. These mountains were formed by the collision continental masses as the ancient Iapetus Ocean closed causing a massive period of mountain building (orogenesis) much in the same way as the Himalayas have been built and are building today. The continent formed by the closure of the Iapetus was only split apart when the N Atalantic opened around 50- 60 Million years ago forming the North American and European Continents.

Off topic I know but I don;t get to talk real geology anymore, even though I work as a geologist!

Moomin

[n1russ]

scotland has indeed sene its first snow couple of days ago on the cairngorms! bring on winter!

[Nick L]

scotland has indeed sene its first snow couple of days ago on the cairngorms! bring on winter!

Yep, the Met Office have issued a yellow, low warning for heavy snow over the Western Highlands as well:

http://www.metoffice.gov.uk/loutdoor/mountainsafety/westhighland/westhighland_latest_pressure.html

[Zerouali lives]

Well we must be approaching that point when we can name this year's survivals???

Not heard from Firefly that much recently - I'm sure he has the answers!

[JRMcLeod]

With North Westerlies forecast in the next few days will the higher elevations get their first snow of the season ?

They already have had the first snow of the season, tuesday morning, the cairngorms were white. Since we are on topic of wishful thinking regarding mountain heights, a new report suggesting that Scotland is rising at 1cm per decade, it would take roughly 790,560years for Ben Nevis to become 7000ft in height

[trebor]

the hills above kinlochleven this morning

all gone now though

[firefly]

Apologies for not updating this thread for ages. I know that there are many on here who like to see how the snow is getting on, and wait with trepidation to see how much (if any) snow is going to survive 'til the first lasting snows of winter!

Firstly, as you've no doubt seen, the first snows of the season have arrived. These arrived on the 1^st October on the Cairngorms, with heavier snow coming a few days later along with strong winds, causing drifting in favoured aspects. Ben Nevis has also seen a good few days of snow, but it has been – thus far – light with little drifting. Some of the snow that fell on the Cairngorms may still be present in sheltered hollows, but we haven't seen good pictures for a couple of days, so it's hard to be certain.

So, what snow still remains on the hills? Well, Garbh Choire Mor on Braeriach (aka Britain's most persistent snow) has the two old faithfulls (Sphinx and Pinnacles) still clinging on. I visited them on the 26^th September and they were in reasonable condition, and the subsequent weather (very cool, with sub-zero temperatures for the best part of 9-days) will have firmed them up. I would expect these patches to survive easily, and the snow that fell on the 4^th October doubtlessly has filled up the gaps around it, preventing air circulation and a degree of melting. These are the only two patches east of the A9.

As for the 'west', Ben Nevis and surrounding hills are still holding on to a bit, but less than last year (and, indeed, 2007). Aonach Mor's snow disappeared some time ago (mid-September), and Aonach Beag's will probably still be there, though we haven't seen pictures of it since the 18^th September, where it was in reasonable nick (40-odd metres long). I'm not 100% sure that this will survive this year, as its low altitude means it's more exposed to melting than snow higher up on Ben Nevis.

Speaking of Ben Nevis, Observatory Gully's main snow looks to be in very good nick. I would astonished if it didn't make it this year, as it looks to be substantial. Regular sorties by helpful local mountain guide Alan Halewood means we have a very good photographic record of the snows there up to a couple of days ago.

In all, it's safe to say that there are 4 Scottish snow patches still extant, with the likelihood of Observatory Gully splitting into 3 before lasting snow arrives. The only issue, as far as I'm concerned, is whether or not my own 'pet' patch of Aonach Beag is going to make it. I'll update this thread when I get more information.

[JRMcLeod]

Apologies for not updating this thread for ages. I know that there are many on here who like to see how the snow is getting on, and wait with trepidation to see how much (if any) snow is going to survive 'til the first lasting snows of winter!

Firstly, as you've no doubt seen, the first snows of the season have arrived. These arrived on the 1^st October on the Cairngorms, with heavier snow coming a few days later along with strong winds, causing drifting in favoured aspects. Ben Nevis has also seen a good few days of snow, but it has been – thus far – light with little drifting. Some of the snow that fell on the Cairngorms may still be present in sheltered hollows, but we haven't seen good pictures for a couple of days, so it's hard to be certain.

So, what snow still remains on the hills? Well, Garbh Choire Mor on Braeriach (aka Britain's most persistent snow) has the two old faithfulls (Sphinx and Pinnacles) still clinging on. I visited them on the 26^th September and they were in reasonable condition, and the subsequent weather (very cool, with sub-zero temperatures for the best part of 9-days) will have firmed them up. I would expect these patches to survive easily, and the snow that fell on the 4^th October doubtlessly has filled up the gaps around it, preventing air circulation and a degree of melting. These are the only two patches east of the A9.

As for the 'west', Ben Nevis and surrounding hills are still holding on to a bit, but less than last year (and, indeed, 2007). Aonach Mor's snow disappeared some time ago (mid-September), and Aonach Beag's will probably still be there, though we haven't seen pictures of it since the 18^th September, where it was in reasonable nick (40-odd metres long). I'm not 100% sure that this will survive this year, as its low altitude means it's more exposed to melting than snow higher up on Ben Nevis.

Speaking of Ben Nevis, Observatory Gully's main snow looks to be in very good nick. I would astonished if it didn't make it this year, as it looks to be substantial. Regular sorties by helpful local mountain guide Alan Halewood means we have a very good photographic record of the snows there up to a couple of days ago.

In all, it's safe to say that there are 4 Scottish snow patches still extant, with the likelihood of Observatory Gully splitting into 3 before lasting snow arrives. The only issue, as far as I'm concerned, is whether or not my own 'pet' patch of Aonach Beag is going to make it. I'll update this thread when I get more information.

Fantastic report, just out of curiosity but i cant quite judge how big the Nevis patch is, do you have any rough idea?

[firefly]

Fantastic report, just out of curiosity but i cant quite judge how big the Nevis patch is, do you have any rough idea?

Thanks.

The photograph from the 8th October shows the main patch split in two. The upper patch is approximately 30-35m wide, with the lower right patch in the region of 15m wide. At present, the upper patch is the largest in Scotland. Hazarding a guess, the maximum width/length of the others are:

1) Observatory Gully - 35m

2) Aonach Beag - ~20-25m

3) Pinnacles (Garbh Choire Mor) ~20m

4) Sphinx (Garbh Choire Mor) ~10m

Strangely, the Sphinx patch - though smallest - is always the last to melt, despite its larger neighbour (Pinnacles) being a mere 30-seconds walk away. This is because of the fact that it is more sheltered from late summer/early autumn sunshine, is slightly higher, and sits tighter to the cliffs than its big brother. Also, they both sit on soil, as opposed to stone. This insulates the base layer, prolonging their life.

Of the patches listed, I would expect them to melt in this order:

1) Aonach Beag (most at risk because of its low altitude 3150 ft)

2) Observatory Gully

3) Pinnacles

4) Sphinx

I hope to visit Aonach Beag on the 24th October, and will take measurements and photos. I'll update on Ben Nevis when I get pictures, which will probably be during the weekend.

[Terminal Moraine]

Excellent reports as always Firefly. I look forward to your updates.

[stewfox]

I hope to visit Aonach Beag on the 24th October, and will take measurements and photos. I'll update on Ben Nevis when I get pictures, which will probably be during the weekend.

I appreciate there is no 'end to the season' as your measuring continued snow cover

However surely patches 10m + will 'survive' if there still there in early November or not ?

In the past what was the latest for a recognised patch to go ?

[firefly]

I appreciate there is no 'end to the season' as your measuring continued snow cover

However surely patches 10m + will 'survive' if there still there in early November or not ?

In the past what was the latest for a recognised patch to go ?

Taking your three points in order:

The 'end' of the season is when lasting snow arrives, thereby ensuring cover until next summer autumn. This is complicated by the fact that the season seldom ends in a single day. What I mean by this is that lasting Cairngorms snow generally arrives earlier than Ben Nevis range. This is further exacerbated by the fact that Aonach Beag's snows lie at 3150 ft, and can take up to two or three weeks longer, dependent on what snow arrives. So, for instance, the Cairngorm season ended last year on the 1st October (when lasting snow arrived), whereas Aonach Mor's and Ben Nevis's wasn't until the 18th of that month. Plus(!), we don't know it's the 'end of the season' until some time after, as snow that falls on the 1st can melt easily during the month of October.

Although patches in excess of 10m are likely to survive, it can't be said that they'll 'surely' survive. Patches that small are very vulnerable to melting because they lack the mass of snow to insulate them from prolonged mild weather. Sure, the days are short and the melting period limited, but it can happen. This leads neatly on to your last point.

In 1994, patches disappeared in December! Temperatures of 10 Celcius plus, combined with extensive muggy hill-fog can be fatal to small patches, and so it proved in 1994. Clear, sunny weather generally isn't as damaging because there's little strength in the sun during November and December, and it doesn't rise anything like high enough to shine on the snow. To give you an idea, Aonach Beag's snow sits below a 1000ft cliff, and is unlikely to see much direct sunlight outside highest summer. Also, if it is clear and sunny during the day then it means it'll be clear and cold overnight, with a frost being probable on the higher hills. Frost is good for snow, firming it up.