Snow patches in Scotland
Long-lying snow patches in Scotland have been noted from at least the 18th century, with snow patches on Ben Nevis being observed well into summer and autumn. Indeed, the summit observatory, which operated from 1883 to 1904, reported that snow survived on the north-east cliffs through more years than it vanished.
More recently, additional and methodical field study on the subject has been carried out by others, most notably by ecologist Dr Adam Watson. Most of this work concentrated on the mountains of north-east Scotland (in particular, the Cairngorms), but more recent observations by him and others has shed light on various locations throughout Scotland where long-lying snow persists. The available information systematically gathered by observers over the last 50 years or so, and greatly increased since the 1990s, has built up a level of knowledge that points to Scotland’s snow patches being now amongst the best documented in the world.
There are many locations on the Scottish mountains where snow lies regularly into July, August and even September, but the two main areas where snow virtually always lies longer than anywhere else are the Cairngorms and the Lochaber mountains. These areas contain all of Scotland's mountains in excess of 4,000 feet (1,219 m), including Ben Nevis.
In some years snow can persist all summer, in some locations lasting through to the next winter. In 2015 some 73 patches were still present in late November at a time when the next winter's snows had started accumulating. The last time so many patches had survived all year was 1994.
Other locations where snow has been known to survive:
- 1. Creag Meagaidh hills, survived in 1994 and 2015
- 2. Glen Affric/Strathfarrar hills, usually melts mid/late August but survivals have been noted on Sgurr na Lapaich, An Riabhachan and Toll Creagach as recently as 2015.
- 3. Ben Wyvis, normally melts July/August, though survival has been noted (A Watson)
- 4. Grey Corries, normally survives until July/August, has survived at least once on Stob Coire Easain (A Watson) and in 2015 on Stob Coire an Laoigh.
- 5. Ben Alder range. Snow has survived at Geal-Charn on multiple occasions, most recently in 2015.
As well as containing five of Scotland's highest mountains, the Cairngorms are the range where snow persists longest, and in more locations, than anywhere else in the UK. Ben Macdui, Cairn Gorm and Braeriach all contain long-lying patches that have been observed for many years.
On Ben Macdui, snow has been known to persist at a few locations from one winter to the next, but the location where more survivals have been noted than any other is grid reference , close to the Garbh Uisge Beag, which drains into Loch Avon. This patch sits at an altitude of 1,060 metres (3,478 ft).
Lying at the north-eastern shoulder of Cairn Gorm is Ciste Mhearad. This hollow contains a patch which, hitherto, was known to persist through many years, but has not done so since 2000. Observations in 2007 and 2008 revealed that September was the month when final melting occurred for this patch. It sits at an altitude of 1,095 metres (3,593 ft) and is located at approximately grid reference .
Braeriach's Garbh Choire Mòr is the place which contains Britain's most persistent snow beds. Snow has been absent from this corrie just 5 times in the last century: 1933, 1959, 1996, 2003 and 2006. Sitting at an altitude of about 1,140 metres (3,740 ft), these patches are located around grid reference ; the two most long-lasting patches are known as "the Pinnacles" and "the Sphinx" after the rock climbs lying above them. It has been claimed that Garbh Choire Mòr (as well as Coire an Lochain in the northern corries) may have contained a glacier as recently as the 19th century.
In 1994, the Cairngorms and surrounding mountains of north-east Scotland had 55 surviving patches, an exceptional number.
Ben Nevis range
As already noted, Ben Nevis has long been known to hold snow late into the year. However, historical reports from the 19th century and early 20th century of snow being ever present on the mountain are virtually impossible to substantiate, so must remain speculative. Nevertheless, what is certainly true is that snow often persists from one winter to the next. Analysis of Ben Nevis's snow is not as comprehensive as that of the Cairngorms, but recent observations show that the last time Ben Nevis was snow-free was late 2006, snow having survived into each winter from 2007 to 2015. The largest patch, at Observatory Gully, sits at an altitude of around 1,130 metres (3,707 ft). The slightly lower patch at Point 5 gully has also been known to survive from one winter to the next.
Aonach Mòr has a corrie known to hold snow from one year to the next: Coire an Lochain. One of these patches, sitting behind a protalus rampart , sometimes survives longer than the patch slightly higher up against the tall cliffs.
Below the cliffs of the north-east ridge on Aonach Beag there is a relatively little known snow-patch which, despite its low altitude (approximately 955 metres (3,133 ft) ), has been Scotland's largest at the time of the arrival of the lasting new winter snows of 2007 and 2008. This patch does not appear in known literature on the subject and this suggests that it is very much under-recorded, which may be because it cannot readily be seen, even from the top of Aonach Mòr or Aonach Beag.
- Newman's Lady-fern – a snow-tolerant species endemic to Scotland.
- Icy Rock-moss – a species found in Cairngorms National Park, where it's typically found on rocks in burns fed by snow patches.
- Younger Dryas
- Ken Crocket, Ben Nevis – Scotland’s highest mountain, ISBN 0-907521-16-9
- Martin Moran, Scotland’s Winter Mountains, ISBN 0-7153-0794-0
- McKenzie, Stephen. "Most snow patches counted in Scotland's hills since 1994". BBC News. Retrieved 27 November 2015.
- Watson, Adam (2011). A Snow Book, Northern Scotland. Paragon Publishing. p. 58.
- "Munros by Altitude". walkhighlands.co.uk. Retrieved 2014-10-01.
- Royal Meteorological Society "Weather" October 2002, vol. 57; Adam Watson, Richard W. Davison & John Pottie
- Royal Meteorological Society "Weather" October 2002, vol. 57; Adam Watson, Richard W Davison & John Pottie
- ":: Winterhighland :: Scottish Snow & Mountain Sports :: Attention all Walkers! 2008 Snow Patch Season". winterhighland.info. Retrieved 2014-10-01.
- Royal Meteorological Society "Weather" March 2007 vol. 62, no. 3; Adam Watson, David Duncan & John Pottie
- Guardian interview with Dr Adam Watson Accessed 8 February 2009
- Harrison S., Rowan, A.V., Glasser, N.F., Knight, J., Plummer, M.A. and Mills, S.C. (2014): Little Ice Age glaciers in Britain: Glacier–climate modelling in the Cairngorm Mountains. The Holocene 24 (2), 135-140. doi:10.1177/0959683613516170
- Kirkbride, M., Everest, J., Benn, D., Gheorghiu, D. and Dawson, A. (2014) Late-Holocene and Younger Dryas glaciers in the northern Cairngorm Mountains, Scotland. The Holocene 24 (2), 141-148.
- http://www.fettes.com/cairngorms/protalus%20rampart.htm protalus rampart
- Royal Meteorological Society "Weather" May 2008 vol. 63, no. 5; Adam Watson, David Duncan, Iain Cameron & John Pottie
-  Video interview with Dr Adam Watson about Cairngorm snow-patches
- Scottish mountain snow melting Speculative BBC feature discussing snow-patch melt and how it may affect mosses, liverworts and birds in the Scottish hills
- Cairngorms Skiing, Feith Buidhe Exploration then ski-ing of a large remaining snow patch at the Feith Buidhe slabs, probably August 1993
- Tower Gully, Ben Nevis Video of Tower Gully being skied on 1 July 1994, showing the phenomenal accumulations of snow that year
- flickr archive Various years' images, as contributed by several people (Dr Adam Watson, Iain Cameron, www.winterhighland.info)