Avalanche Forecast
Regions: Glacier.
Hazard will remain elevated as rising winds and temps form reactive storm slabs through out the park.
Confidence
Moderate
Avalanche Summary
Expect loose dry sluffing in steep terrain.
Thursday/Wednesday: Natural avalanche cycles throughout the highway corridor of loose and slab avalanches failing in the recent storm snow. Avalanches were mostly size 1.5-2, with isolated size 2.5-3.
A natural cornice failure triggered a size 3 deep persistent slab on the SE slope of Grizzly Peak on Saturday.
Snowpack Summary
Warming temperatures and moderate winds will encourage slab formation in the recent 30-40cm of low-density storm snow. Below this snow is old wind-affected surfaces in the alpine/treeline and a melt freeze crust below treeline.
The early Jan surface hoar layers are buried 60-90cm and is most prevalent at treeline. The November 17th facet weakness can still be found near the base of the snowpack in many areas.
Weather Summary
A break between storms on Friday, moderate to strong SW winds continue. The next storm arrives Friday night into Saturday bringing light to moderate precipitation and seasonal temperatures.
Tonight: Clear, Alp Low -6*C, Fz lvl valley bottom, Mod SW winds.
Fri: Flurries, 5 cm, Alp High -5*C, Fz Lvl 1300 m, Mod SW winds.
Sat: Flurries, 7 cm, Alp High -5*C, Fz lvl 1200 m, Mod gusting to strong SW winds.
Terrain and Travel Advice
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- Loose avalanches may start small but they can grow and push you into dangerous terrain.
- Minimize exposure during periods of heavy loading from new snow, wind or rain.
Avalanche Problems
Storm Slabs
Low density storm snow, moderate/strong ridge-top winds, and rising freezing levels are creating storm slabs in the upper snowpack. Watch for signs of a reactive slab such as shooting cracks, recent avalanches and whumphing.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1 - 3
Persistent Slabs
Surface hoar layers formed in the early part of January are gaining strength and are unlikely to be rider triggered. These layers of surface hoar are best preserved at treeline.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 3
Deep Persistent Slabs
Recently, a large cornice-triggered natural avalanche stepped down to this basal layer near Grizzly Peak. Watch for steep, thin rocky areas where this layer could be activated.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 2.5 - 4