White Out (again!)

29th January 2025

A second day of zero visibility above 800m which always provides challenges for the forecasters.  Visibility is crucial for ‘reading’ the landscape and making an assessment of avalanche hazard for recreationalists and forecasters alike.  So, when your world is reduced to a few meters of visibility; there is much more reliance on feeling the snow underneath your feet and visiting a variety of altitudes and aspects that are relevant for the days observations and subsequent avalanche report.

There was a fresh covering of snow down to 600m overnight, this combined with strong NW winds led to some re-distribution of snow onto the leeward aspects.  NE through E to S aspects are affected above 800m. Please reference the main forecast for further detail.

Accumulations of moderately bonded windslab are present in sheltered locations on leeward aspects.  Here in Ciste Mhearad. Travel on foot was difficult due to the variability of underfoot conditions. Soft slab, not so soft slab, weight bearing crust, not weight bearing crust. I’m sure you are starting to get the picture!

The ‘Igloo’ on the summit of Cairngorm 1245m. Good navigation skills were required today. In the centre of the photo you can just make out a small horizontal black line. This is the lid of the container which holds the metrology instruments: it is heated which is why it is not rimed up like the rest of the infrastructure.  This allows the lid to raise and the instrument’s to be exposed for a brief period only to take the required wind and temperature readings. 

Variable underfoot conditions today – an icy breakable crust interspersed with deep drifts.

The granite tor/cairn at 1141 spot height. Rime water ice ‘blobs’ from yesterdays freezing rain overlain with a 4″ growth of rime ice. Rime ice is the only snow/ice feature that ‘grows’ into the prevailing wind. Giving a good indication of the recent wind direction.  (In this case a North-Westerly)

Coire Cas from 600m. Fresh overnight snow down to this level. 

Looking across to Meall a Bhuachaille (810m) 

 

 

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