Navigating around the “white room”…
13th March 2023
The day started with snow falling from the glens upwards, with whiteout conditions in blizzards at even medium elevations above the tree line. The snow continued through much of the day, and although a dry spell is expected overnight, there will be snow showers again tomorrow.
This resulted in poor visibility conditions on Cairn Gorm, with some careful navigation required to ensure that we stayed on the aspects and gradients desired to carry out our observations today.
A complex avalanche situation prevails with new windslab on many aspects either from overnight, or building in the next 24 hours. As such, all aspects will be affected above 800 metres due to the variation in wind direction. The wind will change, but to generalise, will feature a northerly component, as well as being Westerly in the early hours of the morning.
That might give the impression that some northerly aspects will be scoured tomorrow, but it is likely given the wind speeds that cross-loading will occur due to local wind effects. Difficulty in route choice will be made more challenging in poor visibility.
It was also very difficult to judge slope angle today, and many snowballs were thrown to try and get some definition of the slopes. As pictured, it was more pleasant to be alongside the snow fences within the ski area.
Two Avalanche Problems will exist for tomorrow:
Windslab: Unstable windslab will persist on South-East through South-West aspects above 800 metres. Further drifting will result in accumulations of unstable windslab becoming more widespread, and including North-East to East aspects above 800 metres. North-West and North aspects will be subject to cross-loading.
Persistent Weak Layer: Weak layers are persisting at depth in the snowpack. These weak layers are widespread but mainly found above 1000 metres. These weak layers frequently do not give signs of instability and are therefore difficult to manage.
Some more information on ‘Avalanche Problems’ can be found on the SAIS website here: Avalanche Problems Explained.
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