Avalanche Forecast
Regions: South Columbia.
Warm air may destabilize the snowpack and increase the likelihood of avalanche activity. Head out with a conservative mindset and keep things tame.
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
TUESDAY NIGHT: Mostly cloudy with isolated flurries, trace accumulation, 20 to 40 km/h south wind, alpine temperature 2 C, freezing level 2500 m.
WEDNESDAY: Cloudy with afternoon rain or snow, accumulation 1 to 3 cm above the rain-snow line and rain below, 20 to 40 km/h south wind, alpine temperature 1 C, freezing level 2300 m.
THURSDAY: Early-morning snowfall then clear skies, accumulation 5 to 15 cm, 10 km/h northwest wind, alpine temperature -5 C.
FRIDAY: Mostly cloudy with isolated flurries, trace accumulation, 10 km/h southwest wind, alpine temperature -3 C.
Avalanche Summary
A few storm and wind slab avalanches were observed on Monday, occurring within the weekend's storm snow.Â
One persistent slab avalanche was triggered by a rider, occurring on the weak layer described in the Snowpack Summary. It was on an eastern aspect around 1900 m, being 100 cm deep. This falls into the general trend of these persistent slab avalanches, which have been most common between 1800 and 2400 m and on all aspects. This layer must be treated as suspect anywhere it exists.
Snowpack Summary
Freezing levels are forecast to reach well into the alpine Tuesday night and remain for Wednesday. Small amounts of rain may fall, increasing snowpack warming and the likelihood of wet loose avalanches. Above the rain-snow line, wind slabs may exist from recent snow and southwest wind.
A weak layer may be found around 50 to 100 cm deep. The layer consists of surface hoar crystals in treeline terrain in areas sheltered from the wind and otherwise a hard melt-freeze crust associated with weak faceted grains on sun-exposed slopes (i.e., east, south, west). Check out this blog for more information. This layer continues to form large avalanches in the region, although activity may be on a decreasing trend.Â
There are presently no deeper concerns.
Terrain and Travel
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Avalanche Problems
Persistent Slabs
A weak layer may be found around 50 to 100 cm deep. The layer consists of weak faceted grains above a hard melt-freeze crust on sun-exposed slopes and surface hoar in shaded areas sheltered from the wind. Large rider-triggered avalanches continues to occur each day across much of the region.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 2 - 3.5
Loose Wet
Warm air and bits of rain are weakening the snowpack into the alpine. Wet loose avalanches may be triggered out of steep terrain anywhere rain is falling on previously dry snow.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2
Wind Slabs
Wind slabs may be found near the mountain tops above the rain-snow line. Use caution in steep, lee terrain features.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2