This winter’s heavy snowfall in the Moffat hills has caused several avalanches at Carrifran. Most of the snow has come from the west or northwest, which has resulted in a build up of snow on the lee side of the Saddle Yoke ridge.
Les Forster and I set out to do a fence check on the 13th December, but found the fence completely buried in places, so abandoned the walk at the dip between Saddle Yoke and Under Saddle Yoke. Dropping into Rispie Lairs, we found the snow to be waist deep off the ridge, although the level fall of snow was about 45cm. We were back at Carrifran a few days later for the usual Tuesday work, and could see that just to the north of our descent, a stretch of cornice had broken away from under the ridge, with debris spread for several hundred metres below. The same day, Philip Ashmole spotted another fall between Raven Craig and Priest Gill.
Here were further snow falls over the next few weeks and on the Tuesday visit of January 27th there had been a further avalanche on the same line in Rispie Lairs. On February 10th, I was able to go up to see the avalanche and found a few damaged trees, notably one of the few Scots pine in the valley. But with debris to a depth of 1.5m, it will be some time before we can see how much more damage there is to the planting carried out last season. An additional 2000 trees (approximately) had been planted in Rispie Lairs, but much of the ground covered by the debris is wood rush, in which fewer trees will have been placed.
Tuesday February 17th showed several more small avalanches, as with fluctuating temperatures, cornices above steep slopes have become quite unstable.
Previous avalanches at Carrifran have generally been on west or north-western facing slopes from snow which has come from an easterly direction, unlike this winter’s snow.
There was a large slide on 19th January 2010 under Gupe Craig, recorded by John Savory.
Additionally, Philip Ashmole writes: there was another major pair of avalanches in that winter. I first noted them on 9th March 2010 when traversing the slopes below Firthhope Rig. This was at the top of one of the gullies to the left (N) of Firthhope Linn waterfall that are shown here, taken on 22 May 10 (the cascade must be just round the corner to the right).
This photo taken on 29 Jun 10, with snowpack still present, shows the insulating effect of the grass stems brought down by the avalanche, so that the globeflower was out while there was still snow close by.
We can therefore be sure that the steep slopes of the Carrifran valley are at risk of avalanching, the ones recorded seeming to be of the slab type. Which slopes are affected will depend partly on the direction from which the snow came and therefore where there has been a build up of cornices and slabs. Avalanche risk factors are complex, and will include volume of snow, crystal structure, wind speed and direction following snow fall, temperature gradient, angle of slope and layering of previous falls. Following snow falls of over 30cm of snow, it is likely that Carrifran has always been prone to avalanches.
There are records of avalanches in the Lowther Hills about 15 miles to the west of Carrifran on the same weekend as the 2014 Rispie Lairs fall, and others are recorded above Talla reservoir and on the Auchencat Burn SW of Hart Fell, just south of Corehead.
Some weather notes from Met Office relating to the two avalanche sites:
1. Gupe Craig and Firthhope Linn (west and south facing)
17 December 2009
On the 17th, easterly winds brought heavier and persistent snow showers to eastern England and Scotland.
6 January 2010
The synoptic situation in northern Europe settled to a steady northeast wind which brought snow showers and belts of snow.
14 January 2010
Southerly to south-easterly winds brought bands of snow to parts of Scotland and northern England. An inch of snow fell in Glasgow with further accumulations in areas outside the towns and cities, disrupting travel.
2. Rispielairs (east facing)
For much of the month, the UK was under the influence of a westerly weather type, with a sequence of Atlantic depressions tracking across the country. A sequence of particularly deep lows between the 9th and 15th brought some very stormy conditions to Scotland.