This Bulletin Valid Until: Wednesday December 27th, 2017 @ 6 pm.
Main Concerns: (Avalanche problems)
Wind Slab - Wind affect at upper elevations is highly variable with both soft and hard wind slab on leeward slopes in the alpine and exposed treeline areas. These problems are most likely to be encountered on southerly aspects. Natural avalanches are unlikely but these slabs may still be reactive to light loads such as a skier or rider. Avalanches could be large in isolated areas.
Travel/Terrain Advice: Avoid recently wind loaded slopes and rollovers in the alpine and at treeline. Watch and listen for signs of instability such as shooting cracks or whumpfing. Test low consequence slopes and rolls and take note of the aspect, elevation and terrain characteristics. Cold air and snow temperatures will slow bonding and settlement as well as the chance of a lingering avalanche problem.
Past Weather: Clear and cold conditions with light northerly wind and minimal precipitation have been the recent story. Moderate snowfall to sea level on the northeast Island Sunday night made Monday morning festive, but did not produce much accumulation in the mountains.
Avalanche Summary: No avalanches observed.
Snow Pack Description:
Surface - Highly variable distribution of recent storm snow. Exposed crust in all windward (NE-W) alpine and treeline terrain. Pockets of stiff and soft wind slab in lee and protected areas. Sheltered terrain below treeline has low density dry snow of up to 40 cm on the mid December crust.
Upper - Variable dependent on aspect and elevation. 10-40 cm of new snow overlies the old crust layer and has shown poor signs of bonding.
Mid - Well settled.
Lower - Well settled.
Weather Forecast: Dribs and drabs of snow and with cool temperatures and overcast skies for the next 72 hours. Winds will be light and variable.
Mon - 0-3 cm of snow. Winds 30-15 km/h northwest.
Freezing levels of 0-920 m
Tue - 0-5 cm of snow. Winds light west veering to light southwest. 5-20 km/h.
Freezing levels of 0-650 m
Wed - 0-5 cm of snow. Winds southwest 15-20 km/h veering to 10-18 km/h southeast.
Freezing levels of 0-720 m
Prepared by Dan Goodwin