Avalanche Forecast
Issued: Feb 18th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
trettie,
Avalanche Canada
Carefully assess the wind effect as well as new snow amounts as you move through terrain. variable wind direction has been observed.
Summary
Confidence
Avalanche Summary
No significant avalanches were reported in the last couple days but we suspect rider triggerable wind slabs will be found in exposed terrain. On Thursday our field team observed debris from a previous large persistent slab avalanche. At least once a week evidence of large persistent slab avalanches is reported. Keep this in mind when traveling in the backcountry.
Snowpack Summary
Over the past few days southerly winds and new snow has formed large wind slabs on north and east facing slopes. Our field team observed winds coming from a variety of directions so wind slab may exist on all aspects. In sheltered areas recent snow is still soft and likely makes for decent riding.
A hard melt-freeze crust that extends up to about 1700 m is now on the surface in wind-exposed terrain and otherwise buried about 50 to 80 cm in wind-loaded terrain. The crust appears to be bonding to the snowpack.
A weak layer of surface hoar and facets may be buried about 80 to 120 cm deep on north to east aspects in alpine and upper treeline elevations. The layer may rest on a harder melt-freeze crust. Where preserved, this layer has shown to have very high propagation potential and capable of producing large avalanches hundreds of metres wide.
Weather Summary
Saturday Night
Cloudy with up to 10cm of new snow possible. Moderate southwest winds and a low of -6 at 1500m.
Sunday
A mix of sun and cloud with flurries bringing up to 5cm of new snow. Light southwest winds and a high of -6 at 1500m.
Monday
Cloudy with flurries bringing up to 5cm of new snow. Light northerly winds and temperatures at 1500m falling throughout the day to -14.
Tuesday
Mostly clear with the possibility of light flurries bringing trace amounts of new snow. Moderate northerly winds and a high of -15 at 1500m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- The best and safest riding will be on slopes that have soft snow without any slab properties.
Problems
Wind Slabs
Over the past few days southerly winds and new snow has formed large wind slabs on north and east facing slopes. Our field team observed winds coming from a variety of directions so wind slab may exist on all aspects.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
We continue to see periodic avalanches on a weak layer of surface hoar and facets buried about 100 cm deep. Resulting avalanches have propagated for hundreds of metres, with some being remotely triggered from hundreds of metres away. The common trend is that they are on north to east aspects around 1500 to 1700 m in elevation.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Feb 19th, 2023 4:00PM
