We've had continued avalanche activity throughout the week from a variety of triggers: explosives, skiiers, cornices and natural. We are in the upper end of CONSIDERABLE hazard and incoming snow and wind will tip us into HIGH at some point this weekend.
Strong winds over the past week have created windslabs and wind-affected snow surfaces in many exposed areas at treeline and above. Use caution in all leeward areas with wind effect. These avalanches have the potential to start small, but then step down to the deeper weak layers.
Slabs 30-60 cm deep overlie three persistent weak layers formed in January which are a mix of crusts (solar aspect), facets (cold aspects) and isolated surface hoar. We have primarily seen avalanches failing on crusts on solar aspects but are watching for activity on other aspects as well.
This problem is at the base of the snowpack and consists of weak facets and depth hoar near an old crust formed in November. The layer is very weak and will not get stronger anytime soon. Thus the upper snowpack sits on an unstable foundation. This problem exists in most locations and requires avoidance or very careful travel through avalanche terrain.
No new avalanches observed on a Field trip in the Yoho Valley on Thursday. Lots of recent explosive triggered and natural avalanches.
A MIN report of a skiier remote triggering a size 2.5 avalanche in the Healy Creek area on Wednesday from 100m away shows continued reactivity to a skiiers weight.
Windslabs were formed in the alpine and at treeline from last week's snow and extreme winds. These slabs overlie several persistent weak layers that exist 30-60cm below the surface. These weak layers are a combination of crusts, facets and surface hoar formed and buried in January and are producing sudden test results. Deeper in the snowpack, the November crust/facet layer ~40 cm above the ground also continues to produce sudden test results.
A weak frontal system approaches Thursday evening before we switch to a NW flow for Friday and Saturday. Alpine temperatures will be -10 to -15 throughout the period.
Friday: 2- 5 cm forecasted by Friday AM. Clearing Friday with alpine winds moderate to strong from the west.
Saturday: 5 cm throughout the day. Alpine winds moderate from the NW
Sunday: 5-10 cm throughout the day. Alpine winds moderate to strong from the west.
More details can be found in the Mountain Weather Forecast.
