Avalanche Forecast
Issued: Jan 19th, 2025 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
Parks Canada,
Avalanche Canada
Cold temperatures are the main storyline. Be prepared with extra layers and know how to stay warm if your group has an unexpected hiccup.
The persistent slab that we are tracking, down 30-50cm, is still "popping" in snowpack tests. Be cautious if you encounter a pocket of wind slab in committing terrain.
Summary
Confidence
Moderate
Avalanche Summary
A field team conducted explosives testing on steep, northerly Treeline features yesterday. Results up to size 1.5 were observed, with minimal propagation.
On Thursday, there were several large (up to size 2) natural avalanches in the steep terrain on the N face of Mt MacDonald. These were triggered by the extreme SW winds (up to 125km/hr!)
Snowpack Summary
~10cm of cold, faceted snow sits atop a denser, wind-pressed layer. Below this lies a weak interface (Jan 7th layer) down 30-50cm, comprised of surface hoar (all aspects) and/ or a thin crust on steep S aspects.
In the start zone of Mt Fidelity, moderate "resistant" and "sudden planar" snowpack test results were found down 30cm. We are keeping an eye on this persistent layer as the snowpack builds on top of it.
Overall the mid and lower snowpack is strong and well settled.
Weather Summary
Continuing cold, clear, and calm.
Tonight Clear periods. Alpine low -15°C. Ridge winds W-10km/h.
Mon Mainly sunny. Alpine high -13°C. Light SW wind. Alpine temp inversion.
Tues Cloud, sunny periods, isolated flurries. Alpine high -12°C. Winds W 20 gusting 50km/h.
Wed Sun and cloud. Alpine high -8°C. Winds W 10-20km/h.
Terrain and Travel Advice
- Be especially cautious as you transition into wind-affected terrain.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks, or recent avalanches.
Problems
Persistent Slabs
Up to 60cm of snow sits on a persistent weak layer from January 7th. This weak layer has been found in profiles both at treeline and in the alpine. Test results suggest that propagation is still possible on this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 20th, 2025 4:00PM
