Avalanche Forecast
Regions: Glacier.
Avoid overhead avalanche hazard today!
Ongoing strong SW wind may act as a natural trigger, and recent avalanches have been reaching valley bottom.
Weather Forecast
Temperatures and freezing levels dropped with the passage of last nights cold front. More snow is forecast for Monday as another front come through.
Today: Flurries (3cm). Alpine High -9 C. Ridge wind strong SW.
Monday: Flurries (10cm). Alpine Low -10 C, High -5 C. Light S wind.
Tuesday Flurries (7cm). Low -10 C, High -7 C. Light SW wind.
Snowpack Summary
50cm of snow in the past 48hrs and strong to extreme winds from the SW, triggered a widespread avalanche cycle last night. A recent surface hoar layer (Dec 26) is preserved, in isolated areas, down 70+cm. The Dec 13 surface hoar can still be found down 100cm and the Dec 7 crust/facet/surface hoar (aspect/elevation dependent) layer is down 120cm.
Avalanche Summary
There was widespread natural avalanche cycle yesterday morning (small to large), and overnight last night (large-very large).
Artillery control last night produce numerous avalanches up to size 4, notable avalanches from MacDonald West shoulder and Crossover resulted in avalanche deposits on the highway.
Confidence
Wind speed and direction is uncertain on Sunday
Avalanche Problems
Storm Slabs
Heavy snowfall yesterday, accompanied by strong-extreme SW wind, has built thick storm slabs in all open terrain.
A Dec 26 surface hoar may persist below this slab in forest glades at treeline and below.
- The new snow will require several days to settle and stabilize.
- Avoid exposure to overhead avalanche terrain during periods of moderate to intense transport.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely - Very Likely
Expected Size: 2 - 3.5
Cornices
New snow, strong winds and warm temps are a perfect recipe for cornice growth. These could trigger the storm and persistent slabs below.
- Minimize overhead exposure during periods of heavy loading from new snow, wind.
- Stay well back from the leeward side of corniced ridgecrests.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
The additional snow load may be enough to trigger the early december weak layers which are now buried over 1m deep. Field tests last week continued to show these deeper layers still have the potential for skier triggering even at their current depth.
- Be wary of large slopes that did not previously avalanche.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely
Expected Size: 2 - 4