Avalanche Forecast
Issued: Jan 2nd, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
MBender,
Avalanche Canada
There is uncertainty with forecast snowfall amounts Thursday night. If local amounts are 20 cm or greater overnight, avalanche danger may be High.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
Thursday Night: Flurries, accumulation 5-10 cm . Alpine temperature -14 C. Moderate northwest wind.
Friday: Snow, accumulation 10-15 cm. Alpine temperature -4 C. Moderate to strong west wind. Freezing level 1500 m.
Saturday: Snow, accumulation 10-15 cm. Alpine temperature -6 C. Moderate southwest wind. Freezing level 1000 m.
Sunday: Flurries. Alpine temperature -10 C. Moderate southwest wind.
Avalanche Summary
On Wednesday there was a report of a remotely triggered size 2 wind slab avalanche in the alpine as well as numerous naturally triggered storm slab avalanches to size 2 on all aspects.
Reports from Tuesday showed a surface hoar layer buried late December becoming very reactive to skier traffic and ski cutting, producing avalanches to size 2 (large) even on quite low-angle slopes and with remote triggers.
Snowpack Summary
Expect another 5-10 cm of new snow overnight Thursday to add to the 25-40 cm that fell through the New Year's period. All this recent snow has buried a layer of surface hoar found at all elevations. In some places the surface hoar may be combined with sun crust on steep sun-exposed aspects.
A weak layer that was buried at the end of December is now approximately 70 cm deep and may present as surface hoar in sheltered areas, sun crust on steep solar aspects and/or a melt freeze crust below 1700 m.
An additional layer of surface hoar buried mid December is 90-160 cm deep. Avalanche activity on this layer has tapered off, but there is still concern for heavy loads to step down to this layer. A crust from late November is now over 160 cm deep. Concern for this layer is limited to rocky or variable snowpack depth areas in the alpine where it most likely exists as a combination of facets and crust.
Terrain and Travel
- Avoid freshly wind loaded terrain features.
- Watch for fresh storm slabs building throughout the day.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
Problems
Storm Slabs
Snowfall continues to accumulate above a recently buried layer of weak surface hoar. Expect storm slabs to remain reactive as the load builds and temperatures rise.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
There is still concern for heavy loads (storm slab avalanches running) to step down and trigger deeper weak layers buried in December.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 3rd, 2020 5:00PM
