Avalanche Forecast
Regions: Glacier.
More new snow is making for good quality snow sliding throughout the park.
Several weak interfaces buried within the snowpack are becoming less likely to trigger, but still have the potential to produce very large avalanches. Avoid being drawn in to bigger terrain by the good conditions and lack of obvious signs of instability.
Confidence
Moderate
Avalanche Summary
On Friday, a field team on Avalanche Crest triggered a small (size 1.5) storm slab near the ridge crest. We also observed two large natural avalanches in the highway corridor, from the steep North facing MacDonald gullies.
On Thursday, Helicopter bombing at several operations near the park boundary produced large avalanches (up to size 3.0). Many of these were failing at the storm snow/facet interface which was buried on December 23rd.
Snowpack Summary
New snow will likely create a loose dry avalanche problem, as well as adding to the load on recently built storm slabs, up to 70 cm deep.
The Dec. 23rd interface, between last weeks storm snow and the previously weak and facetted snowpack, is strengthening but has been the failure plane for large human triggered avalanches in neighboring areas recently.
The mid-snowpack Dec 05 and Dec 17th surface hoar layers have been unreactive in snowpack tests since last weeks storm.
The Nov 17 surface hoar persists down 80-110 cm, can still be easily found in the snowpack around treeline, and continues to give sudden results in snowpack tests.
Weather Summary
A weakening front affecting the Coast will give unsettled weather to start the weekend. This will be followed by a clearing trend into next week.
Tonight: Fluries, ~10cm of snow. Alpine Low -8*C. Light SW ridgetop wind.
Sat: Flurries, 5cm of snow. Alpine High -7*C, 1200m FZL. Light SW wind.
Sun: Clearing through the day. Alpine low -11*C, High -9*C. Light W wind.
Mon: Mostly Sunny. Low -11*C, High -4*C. Alpine temperature inversion.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Avoid convexities, steep unsupported terrain and rocky outcroppings.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Avalanche Problems
Storm Slabs
There are several potential failure planes within the 50-70cm of storm snow we have received in the last weak. Also, all this new snow fell on a thin and facetted snowpack, creating a weak interface (Dec. 23rd) that continues to show signs of reactivity in neighboring areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1 - 3
Persistent Slabs
Several persistent weak layers are present in the mid to lower snowpack. These layers are still reacting in the moderate to hard range in snowpack tests. Exercise extra caution if you are planning on travelling in areas that haven't seen much traffic yet this season.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 3.5
Loose Dry
Expect fast running sluffs in steeper terrain from the fresh snow that will fall overnight.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2