Wednesday.
30th March 2022
(Above) Debris from a full depth avalanche on Sron a Ghoire.
Estimate it slid yesterday, Tuesday, after sustained mild summit temperatures extending over some days. It’s a ‘frequent-flyer’ location for this type of avalanche at certain times of the year, or under particular weather circumstances. Rocky slabs (as in the photo), or steeply inclined grass slopes are fairly typical bed surface characteristics of full depth (or glide) avalanches. Plenty of lube at the interface between the snow and the underlying surface is also key to encouraging this type of avalanche to slide. (One of the few circumstances when lube isn’t a good thing?)
Full depth avalanches fall outside the scope of our forecasting since they are all but impossible to predict with any degree of accuracy. Same deal with cornice collapse.
(Above) The crownwall was 1m high and approx 30-40m wide and the runout zone extended downhill for 125m. Conservative estimate that 900m³ of compacted moist snow slid downhill when it released. Blocks as large as 1.2m x 1m were common, and debris was 2m deep in places. All things considered, a pretty good size 2 avalanche.
(Above) View across the avalanche debris to Geal Charn 1049m, Creag Pitridh and Beinn a Chlachair. Patchy snow cover in our area. No new snow turned up overnight or during the day but it was really quite cold so all the old snow patches remained refrozen and hard; even those in the sun were quite firm at around midday.
(Above) The Big Picture, taken this afternoon. Tuesday’s full depth avalanche circled in yellow.
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