Avalanche Forecast
Regions: North Columbia.
Warm air is increasing avalanche danger. Conservative terrain travel is recommended given the weather and snowpack conditions.
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
TUESDAY NIGHT: Cloudy with isolated flurries, trace accumulation, 20 to 40 km/h southwest wind, alpine temperature 0 C, freezing level 2200 m.
WEDNESDAY: Cloudy with afternoon rain or snow, accumulation 2 to 5 cm above the rain-snow line and rain below, 20 to 40 km/h southwest wind, alpine temperature -1 C, freezing level 2100 m.
THURSDAY: Early-morning snowfall then clear skies, accumulation 10 to 20 cm, 10 km/h northwest wind, alpine temperature -7 C.
FRIDAY: Mostly cloudy with isolated flurries, accumulation 1 to 3 cm, 10 km/h southwest wind, alpine temperature -6 C.
Avalanche Summary
A few natural storm slab avalanches were observed out of steep terrain on Monday, generally within the top 30 cm of recent snow.
A few more persistent slab avalanches were triggered by riders, being 50 to 70 cm deep, on north to east aspects, and around treeline elevations. This adds to the many avalanches that have released on the weak layer described in the Snowpack Summary over the past couple weeks. This layer must be treated as suspect anywhere it exists.
Snowpack Summary
Freezing levels are forecast to remain around the lower alpine, warming up the snowpack. Small amounts of rain are forecast to fall below around 2000 m on Wednesday, with snow above. Rain will destabilize the snowpack, increasing the likelihood of wet loose avalanches. Up high, 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 appears to be decreasing each day.
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. Riders continue to trigger large avalanches each day across much of the region.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 2 - 3.5
Loose Wet
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: Likely
Expected Size: 1 - 2
Wind Slabs
Wind slabs may be found above the rain-snow line. Use caution in steep, lee terrain features.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2