Northern Cairngorms

NC for 27.12. Heavy snow unstable windslab on W,NW,N aspects abv 800m, avalanches likely. V Poor below also. Haz Considerable

NC for 27.12. Heavy snow unstable windslab on W,NW,N aspects abv 800m, avalanches likely. V Poor below also. Haz Considerable

Forecast Snow Stability: Redistributed lying snow and heavy snowfall will rapidly build deep unstable windslab on mostly West to Northerly aspects above 800m where avalanches are likely. Coire back walls, gullies and crag aprons most affected. NE and SW aspects will also be affected due to cross loading. Below this level and above 500m unstable windslab will build on W to N facing, wind sheltered places such as steep banks and gullies. New cornices will be liable to collapse. The avalanche hazard will be Considerable

Forecast Weather Influences: Dry overnight but with snowfall starting by dawn becoming increasing very heavy and with significant amounts by midday, dying out by the end of the forecast period. Winds will be Storm force South-Easterly, with forecast summit speeds of 120 mph expected. Freezing level around 600 metres overnight rising to 1000 metres by the end of the forecast period. Observed Weather Influences: A dry cold day with summit temperatures around -6 deg C. Winds fresh to Strong Westerly with some drifting at higher elevations. ObservedSnowStability: The old snowpack remnants which mostly lie on North to North-Westerly aspects above 1000 metres is refrozen, firm and stable. A thin layer of unconsolidated snow lies on all aspects but mostly on North through East to South-Easterly aspects above 900 metres, some deeper pockets of poorly bonded windslab are present in wind sheltered places such as terrain hollows, gully tops and coire rims, these are generally isolated and avoidable. The avalanche hazard is Low