2009 - Snow-patches Surviving On Scottish Mountains

[firefly]

Thanks, Arron.

I don't believe there are any left on a southerly or westerly aspect. The last southerly I know of was the Laird's Tablecloth (as the snow-patch is known locally as on upper Deeside), on Beinn a'Bhuird, but this went in late July. I'll make an enquiry on that, though. Good question!

[Terminal Moraine]

One thing that strikes me about the survival of Scottish snow is that whereas in continental Europe the retention of annual ice is commonly associated with how hot and dry the summers are, in Scotland it seems the winters are the bigger factor. For instance summer 1976 was hotter than 1959 yet some snow patches survived, and I remember 1990 and 1995 being down as years with quite high survival (frequent westerly winds and polar maritime incursions in the winter must have helped in all three cases, I think 1995 might also have been helped by repeated spring snowfalls but springs 1976 and 1990 were mostly mild).

I guess that 1959 will have suffered because spring, summer and autumn were all mild, February was very dry and although January was very cold and snowy in north Scotland it was also exceptional for persistence of northerly winds which will have caused a lot of the snow to accumulate on exposed south-facing slopes.

I've got a feeling that survival this year will be below last year but not exceptionally low (maybe close to the 6 that survived in 1999) but only time will tell.

I remember reading in 'Weather' many years ago ( and I really would have to search hard to find it ) that the survivial rate in 1976 was as much down to the persistent dry air, and hence low dew points, during that summer as it was to the accumulation during late winter and into spring. In conditions of high dry bulb and low wet bulb temperature, thawing will be considerably slower than if the dry bulb temp' is lower and the wet bulb higher.

This is frequently the case in winter when, with clear dry air, a dry bulb of several degrees above freezing results in no thawing at all due to the wet bulb remaining below 0c. A weak front then moves in, the dry bulb temp' falls to say 1c, with a wet bulb value about the same, and a steady thaw ensues.

I'm not sure at what point the coolness of a cloudy, wet summer results in the rate of thaw being less than in a dry, sunnier summer with low dew points but there must be a balance point. Does anyone else have an idea?

[Thundery wintry showers]

I have no idea, but thanks for that, because I was unaware that the wet bulb temperature (and presumably by implication humidity and dew point) was an important determining factor on persistence of snow cover, as well as the dry bulb temperature.

My past experiences of snow cover tend to bear that out as well, but it's one of those where "it's only obvious if you know the answer".

[Terminal Moraine]

I'll make the effort to find that article in Weather, I think it was around 1977/78, after the hot summer of 1976.

[Thundery wintry showers]

If you can find which year/month it is I'll be able to access it from the Climatic Research Unit's Library- I think they have it going back to the 1940s.

[firefly]

The statement about dry air melting snow less quickly than wet air is, I think, accurate. Although 1976 was a long, hot summer, it was - naturally - dry. This, coupled with the early arrival of the snow in September, possibly saved the 2 patches that survived that year.

By-the-way, I don't think you'll find anything in Weather about surviving snow-patches on Scottish hills in the mid-'70s. Adam Watson didn't start publishing the annual journal until the mid-'90s. Possibly someone else's work you were reading?

[Terminal Moraine]

By-the-way, I don't think you'll find anything in Weather about surviving snow-patches on Scottish hills in the mid-'70s. Adam Watson didn't start publishing the annual journal until the mid-'90s. Possibly someone else's work you were reading?

P.C Spink, with contributions from Iain Hudson, used to do a regular Scottish snow bed survey in 'Weather' during the 70s and it was in one of his articles I thought I'd seen it. Having said that, I've just looked through all the volumes from 1977-1979 and found no reference to the 'dry air theory' so I'll trawl through the back copies of Journal of Meteorology as it could be in one of those.

[firefly]

Ah, Mr Spink! He was an enthusiast, for sure. The trouble with his field work is that it wasn't done systematically. Nothing wrong with that, of course, but because it was done 'as and when', there are gaps in the data.

Anyway, here are some of his publications:

Spink P C. 1980. A summary of snow surveys in Scotland: 1965-78. Journal of Meteorology 5. 105-111.

Spink P C. 1980. Scottish snow-beds in summer: 1979 survey and some comments on the last 30 years. Weather 35. 256-259.

Spink P C. 1979. Scottish snow beds in summer 1978. Weather 34. 158-160.

Spink P C. 1978. Scottish snow beds in summer 1977. Weather 33. 278-279.

Spink P C. 1974. Scottish snow beds in summer 1973. Weather 29. 151-154

Spink P C. 1973. Scottish snow beds in summer 1972. Weather 28. 162-164.

Edited August 6, 2009 by firefly

[Terminal Moraine]

Ah, Mr Spink! He was an enthusiast, for sure. The trouble with his field work is that it wasn't done systematically. Nothing wrong with that, of course, but because it was done 'as and when', there are gaps in the data.

Yes, I think he did his surveys when he took his summer holiday in Scotland each year. Presumably the missing data is because he didn't go to Scotland or perhaps the weather was so wet he didn't go as far into the mountains as in other years.

[firefly]

Well, I though it was time for an update.

As far as we know, the only patch left north of the Great Glen is on Tom a' Choinnich, where the red dot is. This photograph from yesterday shows it very small, and will be gone in a couple of days. Other than that, all remaining snow in Scotland is to be found in the Cairngorms and Nevis Range.

A cracking photograph from yesterday also shows a 250m long snow-patch on Ben Nevis. Pretty much the same amount of snow as this time last year.

[kippure]

When was the first sleety snow fall of autumn last year. Looking at recent runs on the gfs, quite a couple of runs showing -5 850,s crossing the highlands in fI.

[firefly]

Well, time for an update after a period of inactivity!

I was up Ben Nevis and surrounding hills on Saturday with a couple of fellow chionophiles, and am pleased to report a good covering of snow still remaining in Observatory Gully and a sizeable patch on Aonach Beag. A reasonable amount still on Aonach Mor, but this won't last into October in my opinion.

Firstly, Observatory Gully still holding several patches, the longest of which is 85m long, and deep. Easily as deep as last year, as "]this photograph will show. In addition to this main one, several higher-up ones in Gardyloo Gully are substantial, and a good photograph of them is here.

Aonach Beag's snow is slightly shorter and less massive than last year, but still has a good 70m length.

Aonach Mor's protalus rampart snow is the largest on that hill, but is seriously smaller than 2007 and a fair bit smaller than 2008. It made it by the skin of its teeth last year, but I doubt very much whether it will this year. However, a good picture of it is here.

Some other pictures from that trip are here: http://www.flickr.com/photos/28183399@N03/sets/72157622122803506/

If I were a betting man, I'd say that Aonach Beag and at least one of Nevis's patches will survive this year. However, lasting snow is still a fair bit off. As usual, fingers are crossed.

Edited August 26, 2009 by firefly

[Fozfoster]

Well, time for an update after a period of inactivity!

I was up Ben Nevis and surrounding hills on Saturday with a couple of fellow chionophiles, and am pleased to report a good covering of snow still remaining in Observatory Gully and a sizeable patch on Aonach Beag. A reasonable amount still on Aonach Mor, but this won't last into October in my opinion.

Firstly, Observatory Gully still holding several patches, the longest of which is 85m long, and deep. Easily as deep as last year, as this photograph will show. In addition to this main one, several higher-up ones in Gardyloo Gully are substantial, and a good photograph of them is here.

Aonach Beag's snow is slightly shorter and less massive than last year, but still has a good 70m length.

Aonach Mor's protalus rampart snow is the largest on that hill, but is seriously smaller than 2007 and a fair bit smaller than 2008. It made it by the skin of its teeth last year, but I doubt very much whether it will this year. However, a good picture of it is here.

Some other pictures from that trip are here: http://www.flickr.co...57622122803506/

If I were a betting man, I'd say that Aonach Beag and at least one of Nevis's patches will survive this year. However, lasting snow is still a fair bit off. As usual, fingers are crossed.

Hi Firefly, some great pictures

How deep do you think some of that was?cheers ff

[towbar0]

Forgive my ignorance, but does any snow last all year on mainland GB?

[Norrance]

Thanks for the update Firefly.

How are the Cairngorms patches doing in comparison with last year?

A bit down I would guess?

To Towbar. Yes in most years some snow patches survive in the Scottish Highlands.

[firefly]

Hi Firefly, some great pictures

How deep do you think some of that was?cheers ff

The deepest part of the snow was around 10m, at Observatory Gully. An extraordinary depth for late August, and similar to last year.

Forgive my ignorance, but does any snow last all year on mainland GB?

In the last 100 years, snow has failed to survive in Scotland in only 5 years: 1933, 1959, 1996, 2003 & 2006.

How are the Cairngorms patches doing in comparison with last year?

A bit down I would guess?

Well down. By now there will only be a few patches left outside Garbh Choire Mor on Braeriach. None will survive other than the Garbh Choire Mor ones.

[firefly]

Well, it may be August, but a sign of things to come from MWIS: http://www.mwis.org.uk/mountain/EH.PDF:

"Showers, which for periods may well be frequent, especially north and west from the Cairngorms. Hail and on highest summits sleet."

Winter is on the way...

[towbar0]

The deepest part of the snow was around 10m, at Observatory Gully. An extraordinary depth for late August, and similar to last year.

In the last 100 years, snow has failed to survive in Scotland in only 5 years: 1933, 1959, 1996, 2003 & 2006.

Well down. By now there will only be a few patches left outside Garbh Choire Mor on Braeriach. None will survive other than the Garbh Choire Mor ones.

Hmmmm...

From 1933, 26-37-7-3 gaps.

Long gap from 1959-1996; 37 years. No survival during 1976......??

[Thundery wintry showers]

Indeed, the frequency of years with no survival appears to be increasing, as was acknowledged in one of the recent articles in Weather.

1976 was discussed very recently- I'm told that it came close to recording no survival but then exceptional early snowfalls in September 1976 prevented that from happening.

[Norrance]

Indeed, the frequency of years with no survival appears to be increasing, as was acknowledged in one of the recent articles in Weather.

1976 was discussed very recently- I'm told that it came close to recording no survival but then exceptional early snowfalls in September 1976 prevented that from happening.

Heavy snow did fall to quite low levels in the second week of September. Quite a contrast with less than two weeks before with temps up to 80F.

This was the lasting snow of the following winter in the prone places with substantial falls on the tops.

I was actually camping about two miles North of Aviemore that week and woke up early one morning to find it sleeting.

Edited August 28, 2009 by Norrance

[stewfox]

The deepest part of the snow was around 10m, at Observatory Gully. An extraordinary depth for late August, and similar to last year.

In the last 100 years, snow has failed to survive in Scotland in only 5 years: 1933, 1959, 1996, 2003 & 2006.

Well down. By now there will only be a few patches left outside Garbh Choire Mor on Braeriach. None will survive other than the Garbh Choire Mor ones.

Love these updates

At present would you say this is a 'average year' for snow patch survival or a bit down ?

You mention a 'extraordinary depth' for late August in one area. Is that due to amount of snow that fell in the winter/spring or favourable synoptics this summer ?

I assume the first snow showers wil start falling shortly

[firefly]

Love these updates

At present would you say this is a 'average year' for snow patch survival or a bit down ?

You mention a 'extraordinary depth' for late August in one area. Is that due to amount of snow that fell in the winter/spring or favourable synoptics this summer ?

I assume the first snow showers wil start falling shortly

Slightly below average, I'd say. The Cairngorms are certainly well down, but Ben Nevis and the Aonachs are about where they've been for the last couple of years. That said, Aonach Mor won't last until the new snows unless there's a real heavy, early downfall. Nothing that's happened in the last few years would suggest this is likely.

The depth of Ben Nevis's snow is primarily down to the exceptional falls of February/March. April saw very little snow indeed, and the amount of rain that's fallen this year definitely isn't favourable for snow retention. It's remarkable, actually, that the snow that remains has lasted as long as it has.

Always difficult to say when the first snows will arrive. September saw the first snowfalls of 2007 & 2008, but lasting snow didn't arrive in the west until mid-November in 2007! Contrast this with Garbh Choire Mor's snow, which saw lasting snow arriving on the 1st October 2008! Quite a contrast.

[Norrance]

Thanks again Firefly.

Is there a chance that the Cairngorms [braeriach]snow will not survive this year?

If so and the Nevis range patches survive can I ask if this has happened before to your knowledge?

[firefly]

Thanks again Firefly.

Is there a chance that the Cairngorms [braeriach]snow will not survive this year?

If so and the Nevis range patches survive can I ask if this has happened before to your knowledge?

There's a chance that Braeriach snows will disappear this year, but they're still in pretty good nick. It's amazing how they dig in and seem to consolidate around late-September.

To the best of our knowledge, Ben Nevis's snows have never survived when Braeriach's hasn't. If it were to happen this year then it would be the first time since records began. I, myself, think that there's an outside chance of it happening this year, but wouldn't put a brass farthing on it!

[Fozfoster]

Hi FF got the picture of Gardyloo on my screen saver now. cheers FF