Avalanche Forecast
Regions: South Columbia.
There's uncertainty in what the warming trend will do to the snowpack, but avalanche danger may increase. Head out with a conservative mindset and dial back your terrain choices until the weather cools.
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
MONDAY NIGHT: Cloudy with no precipitation, 20 km/h southwest wind, alpine temperature -5 C, freezing level 1500 m.
TUESDAY: Cloudy with early-morning snowfall, accumulation 1 to 3 cm, 20 to 40 km/h southwest wind, alpine temperature -2 C, freezing level rising to 2000 m.
WEDNESDAY: Mostly cloudy with afternoon snowfall, accumulation 2 to 5 cm snow above the rain-snow line, 20 to 40 km/h southwest wind, alpine temperature 0 C, freezing level 2300 m.
THURSDAY: Clear skies with no precipitation, 10 km/h west wind, alpine temperature -5 C.
Avalanche Summary
Many large (size 2 to 3) storm slab, wind slab, and persistent slab avalanches were triggered by riders, naturally, and using explosives on Sunday. The storm and wind slab avalanches occurred within the weekend's storm snow whereas the persistent slabs released on the weak layer described in the Snowpack Summary. The avalanches occurred on all aspects and elevations between 1900 and 2400 m.
Looking forward, similar avalanche activity is expected to continue on Tuesday. There's uncertainty in exactly what the warming weather will do to the snowpack, so adopting a conservative mindset will be important.
Snowpack Summary
A bit of snow and strong wind are forecast for Tuesday along with a warming trend. New wind slabs may form at high elevations. A spring, moist snowpack exists below around 1500 m. There's uncertainty in what the warming will do, but it has the potential of destabilizing the snowpack and triggering avalanches.
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). This layer continues to form large avalanches in the region. Check out this blog for more information.
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. Substantial avalanche activity continues to occur each day across much of the region.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 2 - 3.5
Wind Slabs
Wind slabs may be found in steep, lee terrain features at higher elevations.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2
Loose Wet
A warming trend may trigger wet loose avalanches out of steep terrain, particularly if the sun pokes through the clouds. Watch your overhead exposure.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 2