Avalanche & cornice debris
20th December 2025
Creag Meagaidh’s first avalanche cycle of the 2025/26 winter season. Saw evidence of seven avalanches and/or cornice collapses in the environs of Coire Ardair today. All relatively small events (size 1 or 0.5) which were almost certainly triggered by the warming event that occurred around midnight 19/20th December. Friday the 19th had been quite a wild day for yesterday’s SAIS ‘Man on The Hill’ who experienced persistent snow showers and drifting above 900m (and rain at lower levels) over the course of the morning/afternoon which then continued into the evening.
Was quite hard to accurately classify these snowy torrents as avalanches, cornice-triggerered avalanches or just simple cornice debris, since visibility up high wasn’t great and identifying crownwall nigh on impossible. However the lobes of snowy debris were pretty easy to spot. N to E aspects was where most of the action was, which was no surprise as Fridays’s strong SW winds had loaded up the sheltered lee slopes.
General snow stability improved quite quickly after the overnight warming had purged instability from the snowpack and initiated avalanches and collapsing cornices. Expecting the freezing level to fall to 900m for a few hours overnight which should further consolidate the snow in most places. A heads up: there are still a few cornices around and these capricious cantilevers of snow need sustained freezing temperatures before they are no longer considered a threat… and it’s going to get noticeably milder again in the morning.
(Above) The crags at the top end of Coire Ardair. Snow on the ground down to about 800m today.
(Above) The NNE-facing crags of the Inner Coire of Coire Ardair with The Window on the far right.
(Above) Looking East and down into the Inner Coire of Coire Ardair. The approach to the summit of The Window was a bit of a stumble-fest through greasy partially snow-covered boulders. The slightly indistinct summit track up to this bealach was covered in soft moist snow of variable depth which made it impossible to find.
(Above) Debris for a minor (size 0.5) avalanche emanating from a short N-facing gully close to the top of The Window.
(Above) Looking across the very steep NNE-facing crags above the Inner Coire. Avalanche debris from Crescent Gully (nearest) and just beyond it a long tongue of what looks like simple cornice debris out of ‘Cinderella’.
(Above) Cornice debris, cornice and slab avalanche debris, or full depth avalanche debris? Or a bit of everything? Not beyond the bounds of possibility that cornice/avalanche debris in transit from up high triggered a minor full depth avalanche at the mid point. A difficult determination. This channelled debris was below The Pipes at the entrance to the Inner Coire of Coire Ardair.
(Above) The Pinnacle, Easy Gully and the Post Face of Coire Ardair today.
(Above) The top of Easy Gully. I think this is cornice debris from the minor cornice line that sometimes forms on the steep E-facing part of the Post Face just as you top out of Easy Gully. The poor visibility again hampered crownwall identification so there could be some avalanche debris mixed in with it as well.
(Above) Cornice and avalanche debris in a N-facing gully in Coire Ardair that’s close to the summit of Puist Coire Ardair. Yesterday, Mark identified quite a distinct cornice line in his blog posting (4th photo) and this shot, from almost the reverse angle, illustrates the upshot from the overnight warming event.
(Above) The steep ENE-facing backwall of Coire a Chriochairein. The red line shows the track of what was probably a cornice-triggered avalanche event in this quiet coire. If you click on the photo you might get a better impression of the debris in the run-out zone. A wide slide path which was partly channelled down low. However not a huge amount of debris as the unstable snow was limited to 20m to 30m immediately below the cornice line.
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