Avalanche Forecast
Issued: Feb 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Persistent Slabs and Deep Persistent Slabs.
mconlan,
Avalanche Canada
Storm and wind slabs continue to be reactive. Cold weather increases the consequence of any incident.
Summary
Confidence
Moderate
Avalanche Summary
Widespread storm slab and wind slab avalanche activity occurred on Tuesday, mostly releasing within Monday night's storm snow. The avalanches were on all aspects and within all elevation bands and were generally small to large (size 1 to 3).
Numerous naturally triggered large to very large (size 2.5 to 3.5) persistent slab and deep persistent slab avalanches were observed on Monday and Tuesday. They occurred on all aspects between 1700 and 2700 m.
Looking forward, we suspect that storm and wind slab avalanches will continue to be triggerable by riders as all the recent snow slowly bonds to the snowpack. Triggering deeper layers remains possible, particularly on shallow, rocky slopes.
Snowpack Summary
Storm slabs formed from Monday night's 20 to 50 cm of snow. The snow fell with southwest wind which has now switched to easterly wind, meaning wind slabs may be found on all aspects.
Around 80 to 100 cm of snow may overly a small layer of surface hoar crystals that was buried mid-February. This layer is most likely found around treeline elevations in areas sheltered from the wind. The remainder of the mid-pack hosts various old layers of surface hoar, facets, and melt-freeze crusts that are gaining strength and bonding to the snowpack. Periodic reports of large avalanches on these layers are a reminder of the complicated snowpack in this region.
A layer of large and weak facets that formed in November is found near the base of the snowpack. The layer is slowly gaining strength but sporadic and very large avalanches continue to provide evidence that this layer cannot be trusted.
Weather Summary
Wednesday Night
Partly cloudy with no precipitation, 20 km/h east wind, treeline temperature -23 °C.
Thursday
Mostly clear skies with no precipitation, 20 km/h east wind, treeline temperature -22 °C.
FridayClear skies with no precipitation, 10 to 20 km/h west wind, treeline temperature -21 °C.
SaturdayCloudy with snowfall, accumulation 5 to 10 cm, 20 to 40 km/h south wind, treeline temperature -15 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Give the new snow several days to settle and stabilize before pushing into bigger terrain.
- Good day to make conservative terrain choices.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Storm Slabs
Touchy storm slabs are widespread. Wind slabs are also found in wind-exposed terrain on all aspects due to southwest wind shifting to easterly wind. Expect human-triggered storm and wind slab avalanches to be likely on all aspects.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Problematic weak layers are becoming spotty across the region, however recent large persistent slab avalanche observations continue to trickle in reminding us that these layers remain a concern.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer continues to sporadically produce very large avalanches. Human triggering is most likely in steep, shallow terrain, or by triggering a smaller avalanche that could step down to this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 23rd, 2023 4:00PM
