"Any time when there has been snow and it is not consolidated - and there is a lot of wind - you get a lot of what we call wind slab
But while trying to reach the peak they realised they were standing on a wind slab
- a tough layer of snow resting on a softer and more precarious surface.
On their main route to the summit, they discovered they were walking on 'wind slab
' - a hard crust of snow sitting on a softer layer.
Mr Blyth Wright, SAIS co-ordinator, said his team had said on Monday that there would be a substantial risk of avalanches in the Category Three class, with the report for the Lochaber area warning climbers that strong southerly winds had deposited fresh wind slab
in sheltered locations.
The rock was shattered loose and the snow dangerous wind slab
. I reached the top at 1500 hours, followed by the Dane and two Russians.