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.
Have a happy new year!
Confidence
Moderate
Avalanche Summary
On Saturday, we observed a few natural avalanches up to size 2.5 from steep terrain in the highway corridor. These were starting as loose dry avalanches from steep unskiable terrain, with some triggering storm slabs on planar slopes below.
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.
Helicopter bombing at several operations near the park boundary has produced large avalanches recently (up to size 3.0). Many of these were failing at the storm snow/facet interface which was buried on December 23rd.
Snowpack Summary
20-30cm of low density new snow has created 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 building ridge of high pressure will give a clearing trend into next week.
Tonight: Isolated fluries. Alpine Low -9*C. Light SW ridgetop wind.
Sunday: Clearing through the day. Alpine High -9*C. Light West wind.
Monday: Mostly Sunny. Low -8*C, High -3*C. Light South wind.
Tuesday: Mostly Sunny. Low -12*C, High -4*C. Light SW wind.
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 week. 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
Up to 25cm of fresh snow has created a loose dry problem in steep terrain. These small avalanches could have consequences if they push you into terrain traps or over cliffs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2