Improved cover for the New Year
31st December 2023
The snow cover has improved significantly from yesterday, with fresh snow and accumulations in sheltered locations due to the strong winds. This has filled in Coire Cas a bit more, where some drifting has occurred around the snow fences. The crags in Coire an t-Sneachda looked particularly alluring with a nice white cover.
At around 950-1000 metres some shallower windslab deposits were found to be particularly sensitive where they overlie a fine crust. This was likely to have formed last night during some transient spikes in the temperature before a return to colder conditions. The Cairn Gorm summit weather station briefly registered temperatures of around -0.2 degrees Celsius.
Above 1000 metres windslab has been deposited in steep wind sheltered areas, mainly of a South-West through West to North-East aspects. More localised accumulations are present down to 800 metres. Areas affected include coire rims, gullies, and particularly gully tops which can be considered as being multi aspect bowls. Deposition was also noted in steep coire head walls, resulting in unsupported convex “bulges”, see the image below.
As the wind backs to come from a south-westerly direction there will be redistribution of the existing windslab, making for a more widespread distribution. The avalanche hazard will be Moderate.
Happy New Year from the SAIS Northern Cairngorms team. We will be out again as usual tomorrow in 2024!
These thin windslabs were particularly reactive, failing easily evidenced by the shooting cracks visible at the top of this image.
Note the bulging convexity on the centre left of this image – the headwall of Coire Cas. This represents windslab deposited in the last 24 hours. The lower slopes will have thinner accumulations relative to those above, leaving the snow above unsupported. Evidence of natural avalanches will be absent, but human triggering is possible, especially where the snowpack is shallower.
A North-West to West facing aspect at around 1100 metres (Windy Col just to the east of Stop Coire an t-Sneachda). Notice the localised windslab accumulation and cornices around the coire rim due to last nights wind speeds. Poorly bonded windslab will be found in these locations.
A solitary figure in Aladdin’s Couloir, Coire an t-Sneachda. Taken with a long lens, they seemed to be moving slowly from a distance.
The mist cloud trying to break from the summit of Cairn Gorm. The summit weather station was covered in thick rime, vastly reducing the wind speed and direction data from last night.
A fleeting glimpse of Sgor Gaoith and Sgoran Dubh Mor from Cairn Gorm summit.
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James Hotchkis
31st December 2023 6:35 pm
The “solitary figure” today in Alladins Couloir was me!
Your reports are hugely appreciated.
I was very conscious of slab, dug a pit and considered it was OK. I did try to keep to the left wall of the gully.
Siobhan
31st December 2023 8:39 pm
Chatted to the guy who you photographed in Aladin’s. He said it was grand. He didn’t see any windslab and the ice bit wasn’t in condition at the bottom.
ncairngormsadmin
4th January 2024 3:17 pm
Thanks Siobhan, Yes he was in touch.