Avalanche Forecast
Regions: Glacier.
The hazard will ramp up through out the day tomorrow as new snow piles up, and winds and temperatures increase.
Be increasingly conservative in your decision making as the day progresses.
Weather Forecast
A low pressure system drives a warm front our way, giving snowfall Friday.
Tonight: Flurries (5cm). Alpine low -9*C. Moderate SW ridgetop winds
Fri: Snow (15-20cm during the day, with 10cm more overnight). High -7*C. Strong SW wind
Sat: Isolated flurries. Low -9*C, High -6*C. Strong W wind
Sun: Mix of sun and cloud. Low -7*C, High -2*C. Mod SW wind
Snowpack Summary
Up to 25cm of new snow by Friday PM, combined with strong SW wind, will load up lee features with fresh storm slabs. This brings the total to 40-70cm on the drought interfaces from Jan 29th - surface hoar (5-15mm) on sheltered/shady slopes, wind effect in exposed areas, and a suncrust on solar aspects. The Dec 1 crust/facet combo is down 1.5-2.5m.
Avalanche Summary
On Thursday, a field crew at Fidelity had a significant whumpf.
Wednesday, avalanche control in Cougar Corner and on Abott produced several size 2 slab avalanches.
Tuesday, a crew on Abbott easily ski cut sz 1-1.5 slab avalanches on convex rolls.
On Monday, natural activity was widespread at all elevations (storm slabs failing on the Jan 29th layer).
Confidence
Forecast snowfall amounts are uncertain
Avalanche Problems
Storm Slabs
New snow will fall as low density powder at the start of the storm, and become stiffer as the winds and temperatures increase. This is a perfect recipe for storm slabs.
- Use caution in lee areas. The storm snow is forming reactive slabs.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2.5
Persistent Slabs
The Jan 29th interface is buried up to 60cm deep - and is likely to trigger on open slopes without previous activity.
New snow is making it difficult to assess which slopes have avalanched, avoid avalanche terrain unless you have this knowledge.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
- Be aware of the potential for wide propagations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3
Loose Dry
Expect loose dry avalanches in steep terrain that is sheltered from the wind.
These have the potential to step/gouge down to the Januarty 29th interface and and gain significant mass.
- Avoid overhead exposure during periods of heavy loading from new snow and/or wind.
- Be aware of party members below you that may be exposed to your sluffs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2.5