Avalanche Forecast
Issued: Nov 29th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
Ian Jackson,
Despite the recent strong winds, good skiing can be found in many areas. Avalanche conditions seem pretty good, but a rogue large avalanche on Sunday reminds us of the lurking instabilities in the snowpack.
Summary
Weather Forecast
Dry and warm conditions for the next few days. Monday, we may see up to 5 cm of new snow, with winds increasing to strong SW. Tuesday will be dry with decreasing winds from the NW. On Wednesday we may see warm alpine temperatures and the possibility of an inversion.
Snowpack Summary
Variable surface conditions exist with hard windslabs in exposed locations and softer snow in more sheltered areas. The Nov 5 facet/crust combo is down 50-80 cm and producing variable test results, but 'sudden' in fracture character. This crust extends up to 2500 m on N aspects and higher on solar aspects. Snow depths at treeline are 70-130 cm.
Avalanche Summary
Minimal avalanche activity observed today at local ski hills and on a ski tour in the Watermelon Peak area. The exception to this was a large avalanche that was witnessed at around 11 am by a member of the public on the west aspect of Dolomite Peak. It was a size 2.5 that ran in a cross loaded gully feature with minimal weather inputs to trigger it
Confidence
Due to the number of field observations
Problems
Wind Slabs
Windslabs exist in exposed alpine areas from big winds on Friday and Saturday. Give these time to bond and be cautious if you are in steep wind affected terrain.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The Nov 5 crust has facets growing above and below it, and exists up to 2500m on shady aspects and higher on solar aspects. We haven't seen much activity on this layer yet, but a large avalanche failed naturally on this layer on Sunday.
- Be aware of thin areas that may propogate to deeper instabilites.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 30th, 2020 4:00PM
